gzip integer overflow
eventfd double close
netrc and default credential leak
cURL libcurl could allow a remote attacker to bypass security restrictions, caused by a flaw when using OCSP stapling to validate server cerficate. By sending a specially crafted request, an attacker could exploit this vulnerability to establish the connection even if the certificate is revoked.
Accounts. The issue was addressed with improved checks.
Accounts. The issue was addressed with improved checks.
Accounts. The issue was addressed with improved checks.
Accounts. The issue was addressed with improved checks.
Last updated 10 July 2026
Last updated 24 July 2024
cURL libcurl could allow a remote attacker to bypass security restrictions, caused by a mixed case flaw when curl is built without PSL support. By sending a specially crafted request, an attacker could exploit this vulnerability to allow a HTTP server to set "super cookies" in curl.
Last updated 2 July 2026
env-set cross-proxy Digest auth state leak
A path traversal vulnerability exists in curl <8.0.0 SFTP implementation causes the tilde (~) character to be wrongly replaced when used as a prefix in the first path element in addition to its intended use as the first element to indicate a path relative to the user's home directory. Attackers can exploit this flaw to bypass filtering or execute arbitrary code by crafting a path like /~2/foo while accessing a server with a specific user.
A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input thereby enabling attackers to execute arbitrary code on the system.
A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functionality to behave incorrectly when multiple URLs are requested in parallel. Using its HSTS support, curl can be instructed to use HTTPS instead of using an insecure clear-text HTTP step even when HTTP is provided in the URL. This HSTS mechanism would however surprisingly fail when multiple transfers are done in parallel as the HSTS cache file gets overwritten by the most recentlycompleted transfer. A later HTTP-only transfer to the earlier host name would then not get upgraded properly to HSTS.
A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functionality fail when multiple URLs are requested serially. Using its HSTS support, curl can be instructed to use HTTPS instead of usingan insecure clear-text HTTP step even when HTTP is provided in the URL. ThisHSTS mechanism would however surprisingly be ignored by subsequent transferswhen done on the same command line because the state would not be properlycarried on.
An allocation of resources without limits or throttling vulnerability exists in curl <v7.88.0 based on the "chained" HTTP compression algorithms, meaning that a server response can be compressed multiple times and potentially with differentalgorithms. The number of acceptable "links" in this "decompression chain" wascapped, but the cap was implemented on a per-header basis allowing a maliciousserver to insert a virtually unlimited number of compression steps simply byusing many headers. The use of such a decompression chain could result in a "malloc bomb", making curl end up spending enormous amounts of allocated heap memory, or trying to and returning out of memory errors.
A vulnerability exists in curl <7.87.0 HSTS check that could be bypassed to trick it to keep using HTTP. Using its HSTS support, curl can be instructed to use HTTPS instead of using an insecure clear-text HTTP step even when HTTP is provided in the URL. However, the HSTS mechanism could be bypassed if the host name in the given URL first uses IDN characters that get replaced to ASCII counterparts as part of the IDN conversion. Like using the character UTF-8 U+3002 (IDEOGRAPHIC FULL STOP) instead of the common ASCII full stop (U+002E) .. Then in a subsequent request, it does not detect the HSTS state and makes a clear text transfer. Because it would store the info IDN encoded but look for it IDN decoded.
A use after free vulnerability exists in curl <7.87.0. Curl can be asked to tunnel virtually all protocols it supports through an HTTP proxy. HTTP proxies can (and often do) deny such tunnel operations. When getting denied to tunnel the specific protocols SMB or TELNET, curl would use a heap-allocated struct after it had been freed, in its transfer shutdown code path.
A vulnerability was found in curl. The issue occurs if curl is told to use an HTTP proxy for a transfer with a non-HTTP(S) URL. It sets up the connection to the remote server by issuing a CONNECT request to the proxy and then tunnels the rest of the protocol through. An HTTP proxy might refuse this request (HTTP proxies often only allow outgoing connections to specific port numbers, like 443 for HTTPS) and instead return a non-200 response code to the client. Due to flaws in the error/cleanup handling, this could trigger a double-free issue in curl if using one of the following schemes in the URL for the transfer: dict, gopher, gophers, ldap, ldaps, rtmp, rtmps, telnet.
A vulnerability was found in curl. The issue occurs because curl's HSTS check can be bypassed to trick it to keep using HTTP. Using its HSTS support, it can instruct curl to use HTTPS directly instead of using an insecure clear-text HTTP step even when HTTP is provided in the URL. This mechanism can be bypassed if the hostname in the given URL uses IDN characters that get replaced with ASCII counterparts as part of the IDN conversion. Like using the character UTF-8 U+3002 (IDEOGRAPHIC FULL STOP) instead of the common ASCII full stop (U+002E) ..
Accelerate. An out-of-bounds read was addressed with improved bounds checking.
When doing SSH-based transfers using either SCP or SFTP, and asked to do public key authentication, curl would wrongly still ask and authenticate using a locally running SSH agent.
A vulnerability found in curl. This security flaw happens when curl is used to retrieve and parse cookies from an HTTP(S) server, where it accepts cookies using control codes (byte values below 32), and also when cookies that contain such control codes are later sent back to an HTTP(S) server, possibly causing the server to return a 400 response. This issue effectively allows a "sister site" to deny service to siblings and cause a denial of service attack.
curl can be told to parse a .netrc file for credentials. If that file endsin a line with 4095 consecutive non-white space letters and no newline, curlwould first read past the end of the stack-based buffer, and if the readworks, write a zero byte beyond its boundary.This will in most cases cause a segfault or similar, but circumstances might also cause different outcomes.If a malicious user can provide a custom netrc file to an application or otherwise affect its contents, this flaw could be used as denial-of-service.
A vulnerability was found in curl. The issue occurs when doing HTTP(S) transfers, where curl might erroneously use the read callback (CURLOPTREADFUNCTION) to ask for data to send, even when the CURLOPTPOSTFIELDS option has been set if it previously used the same handle to issue a PUT request which used that callback. This flaw may surprise the application and cause it to misbehave and either send off the wrong data or use memory after free or similar in the subsequent POST request.
A vulnerability was found in curl. This issue occurs because the number of acceptable "links" in the "decompression chain" was unbounded, allowing a malicious server to insert a virtually unlimited number of compression steps. This flaw leads to a denial of service, either by mistake or by a malicious actor.
A vulnerability was found in curl. This issue occurs because when curl saves cookies, alt-svc, and HSTS data to local files, it makes the operation atomic by finalizing the process with a rename from a temporary name to the final target file name. This flaw leads to unpreserved file permissions, either by mistake or by a malicious actor.
A vulnerability was found in curl. This issue occurs because it mishandles message verification failures when curl does FTP transfers secured by krb5. This flaw makes it possible for a Man-in-the-middle attack to go unnoticed and allows data injection into the client.