A vulnerability was found in the libxml2 library. There exist a possible format string vulnerability.

https://bugzilla.gnome.org/showbug.cgi?id=761029

Upstream fixes:

https://git.gnome.org/browse/libxml2/commit/?id=4472c3a5a5b516aaf59b89be602fbce52756c3e9 https://git.gnome.org/browse/libxml2/commit/?id=502f6a6d08b08c04b3ddfb1cd21b2f699c1b7f5b

Buffer overflow in libxml2 allows remote attackers to execute arbitrary code by leveraging an incorrect limit for port values when handling redirects.

The libxml2 library, as used in multiple products, could allow a remote attacker to execute arbitrary code on the system, caused by a memory corruption error. An attacker could exploit this vulnerability using a specially crafted XML document to execute arbitrary code on the system or cause a denial of service.

Heap-based buffer overflow in the xmlParseAttValueComplex function in parser.c in libxml2 before 2.7.0 allows context-dependent attackers to cause a denial of service (crash) or execute arbitrary code via a long XML entity name.

The htmlParseComment function in HTMLparser.c in libxml2 allows attackers to obtain sensitive information, cause a denial of service (out-of-bounds heap memory access and application crash), or possibly have unspecified other impact via an unclosed HTML comment.

A flaw in libxml2 allows remote XML entity inclusion with default parser flags (i.e., when the caller did not request entity substitution, DTD validation, external DTD subset loading, or default DTD attributes). Depending on the context, this may expose a higher-risk attack surface in libxml2 not usually reachable with default parser flags, and expose content from local files, HTTP, or FTP servers (which might be otherwise unreachable).

A vulnerability was found in the libxml2 library. A heap-buffer-overflow could happen in xmlStrncat.

References:

https://bugzilla.gnome.org/showbug.cgi?id=763071

Upstream fix:

https://git.gnome.org/browse/libxml2/commit/?id=8fbbf5513d609c1770b391b99e33314cd0742704

An integer overflow, leading to heap-based buffer overflow was found in the way libxml, XML files manipulation library, processed certain XPath expressions. A remote attacker could provide a specially-crafted XML file, which once opened in an application linked against libxml would cause that application to crash, or, potentially, execute arbitrary code with the privileges of the user running the application.

References: [1] http://scarybeastsecurity.blogspot.com/2011/05/libxml-vulnerability-and-interesting.html [2] http://www.openwall.com/lists/oss-security/2011/05/31/5 [3] http://www.openwall.com/lists/oss-security/2011/05/31/8

Upstream patch: [4] http://git.gnome.org/browse/libxml2/commit/?id=d7958b21e7f8c447a26bb2436f08402b2c308be4

A vulnerability was found in the libxml2 library. A heap-buffer overflow could happen in xmlFAParsePosCharGroup

References:

https://bugzilla.gnome.org/showbug.cgi?id=757711

Upstream fix:

https://git.gnome.org/browse/libxml2/commit/?id=cbb271655cadeb8dbb258a64701d9a3a0c4835b4

GNOME libxml2 is vulnerable to a buffer overflow, caused by improper bounds checking by the xmlEncodeEntitiesInternal function in libxml2/entities.c. By persuading a victim to open a specially-crafted file, a remote attacker could overflow a buffer and execute arbitrary code on the system.

NULL Pointer Dereference allows attackers to cause a denial of service (or application crash). This only applies when lxml is used together with libxml2 2.9.10 through 2.9.14. libxml2 2.9.9 and earlier are not affected. It allows triggering crashes through forged input data, given a vulnerable code sequence in the application. The vulnerability is caused by the iterwalk function (also used by the canonicalize function). Such code shouldn't be in wide-spread use, given that parsing + iterwalk would usually be replaced with the more efficient iterparse function. However, an XML converter that serialises to C14N would also be vulnerable, for example, and there are legitimate use cases for this code sequence. If untrusted input is received (also remotely) and processed via iterwalk function, a crash can be triggered.

A vulnerability was found in a way libxml2 parses certain files. With the libxml2 in recovery mode, a maliciously crafted filed could cause libxml2 to crash.

References:

http://seclists.org/oss-sec/2016/q1/682

CVE assignment:

http://seclists.org/oss-sec/2016/q1/683

A vulnerability was found in the libxml2 library. A maliciously crafted file could cause the application to crash due to a heap-based buffer underread in xmlParseName.

References:

https://bugzilla.gnome.org/showbug.cgi?id=759573

Upstream fix:

https://git.gnome.org/browse/libxml2/commit/?id=00906759053986b8079985644172085f74331f83

A vulnerability was found in libxml2. Parsing a maliciously crafted xml file could cause the application to crash if recover mode is used.

References:

http://seclists.org/oss-sec/2016/q2/195

It is possible to trigger a stack overflow using a carefully crafted invalid xml file, the stack overflow occurs before libxml2 determines the xml file is invalid.

Upstream bug:

https://bugzilla.gnome.org/showbug.cgi?id=765207

It was found that Red Hat JBoss Core Services erratum RHSA-2016:2957 for CVE-2016-3705 did not actually include the fix for the issue found in libxml2, making it vulnerable to a Denial of Service attack due to a Stack Overflow. This is a regression CVE for the same issue as CVE-2016-3705.

Multiple use-after-free vulnerabilities in libxml2 2.9.0 and possibly other versions might allow context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via vectors related to the (1) htmlParseChunk and (2) xmldecldone functions, as demonstrated by a buffer overflow in the xmlBufGetInputBase function.

dict.c in libxml2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via an unexpected character immediately after the "<!DOCTYPE html" substring in a crafted HTML document.

The xslextfunctionphp function in ext/xsl/xsltprocessor.c in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13, when libxml2 before 2.9.2 is used, does not consider the possibility of a NULL valuePop return value before proceeding with a free operation after the principal argument loop, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted XML document, a different vulnerability than CVE-2015-6837.

The xslextfunctionphp function in ext/xsl/xsltprocessor.c in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13, when libxml2 before 2.9.2 is used, does not consider the possibility of a NULL valuePop return value before proceeding with a free operation during initial error checking, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted XML document, a different vulnerability than CVE-2015-6838.

A vulnerability was found in the libxml2 library. The parser would fetch content of an external entity while not in validating mode.

References:

https://bugzilla.gnome.org/showbug.cgi?id=761430

Upstream fix:

https://git.gnome.org/browse/libxml2/commit/?id=b1d34de46a11323fccffa9fadeb33be670d602f5

A vulnerability in libxml2 was found causing DoS by exhausting CPU when parsing specially crafted XML document.

Upstream bug:

https://bugzilla.gnome.org/showbug.cgi?id=756733

It was discovered, that libxml2 does not properly handle long XML entity names. In the xmlParseAttValueComplex() function in parser.c, when entity name is not substituted with entity value, but is sent to output unchanged, buffer used to store entity name may not be grown sufficiently in case of long entity names, resulting in a heap buffer overflow.

Issue is already fixed upstream in version 2.7.0.

A heap-buffer overflow was found in the way libxml2 decoded certain XML entitites. A remote attacker could provide a specially-crafted XML file, which once opened in an application linked against libxml would cause that application to crash, or, potentially, execute arbitrary code with the privileges of the user running the application.

Reference: http://googlechromereleases.blogspot.in/2012/11/stable-channel-update.html

Patch: http://git.gnome.org/browse/libxml2/commit/?id=6a36fbe3b3e001a8a840b5c1fdd81cefc9947f0d

A denial of service flaw was found in the way libxml2, a library providing support to read, modify and write XML and HTML files, performed string substitutions when entity values for external entity references replacement (--noent option) was requested / enabled during the XML file parsing. A remote attacker could provide a specially-crafted XML file containing an external entity expansion, when processed would lead to excessive CPU consumption (denial of service).

This a different flaw from CVE-2013-0338.

Upstream patch:

http://git.gnome.org/browse/libxml2/commit/?id=23f05e0c33987d6605387b300c4be5da2120a7ab

The xmlParseConditionalSections function in parser.c in libxml2 does not properly skip intermediary entities when it stops parsing invalid input, which allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) via crafted XML data, a different vulnerability than CVE-2015-7941.

It was found that Red Hat JBoss Core Services incorrectly fixed CVE-2016-3627 in Apache HTTP 2.4.23 (erratum RHSA-2016:2957), leaving libxml2 vulnerable to a Denial of Service attack via stack consumption.

Daniel Veillard discovered that a specially crafted document can lead to a recursive evaluation of entities, the result being an exhaustion of memory and CPU usage

Acknowledgements:

Red Hat would like to thank Andreas Solberg for responsibly disclosing this issue.

Multiple use-after-free vulnerabilities in libxml2 2.5.10, 2.6.16, 2.6.26, 2.6.27, and 2.6.32, and libxml 1.8.17, allow context-dependent attackers to cause a denial of service (application crash) via crafted (1) Notation or (2) Enumeration attribute types in an XML file, as demonstrated by the Codenomicon XML fuzzing framework.

An out-of-bounds read flaw was reported in libxml2's htmlParseNameComplex() function:

http://seclists.org/oss-sec/2016/q1/199

A remote attacker could provide a specially crafted XML file that, when processed by an application linked against libxml2, could cause the application to disclose crash.