CVE-2026-11979
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
Multiple stack-based buffer overflows were discovered in the xmlcatalog utility of libxml2 when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking. Supplying an overly long input line can overflow internal buffers (command, arg, and argv) during input parsing.
Risk Assessment
Successful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process. This poses a risk to organizations if xmlcatalog is used in production environments or automation scripts.
Recommendation
Update libxml2 to a version containing the fix from commit c2e233fc. If an update is not possible, avoid using the xmlcatalog utility in --shell mode with untrusted input.
Other vulnerabilities in libxml2
See all- CVE-2017-7013High
An issue was discovered in certain Apple products related to the 'libxml2' component. Affects iOS before 10.3.3, macOS before 10.12.6, iCloud before 6.2.2 on Windows, iTunes before 12.6.2 on Windows, tvOS before 10.2.2, and watchOS before 3.2.3.
- CVE-2017-7010High
An issue was discovered in certain Apple products related to the 'libxml2' component. It affects iOS before 10.3.3, macOS before 10.12.6, iCloud before 6.2.2 on Windows, iTunes before 12.6.2 on Windows, and tvOS before 10.2.2.
- CVE-2016-4483High
The xmlBufAttrSerializeTxtContent function in xmlsave.c in libxml2 allows context-dependent attackers to cause a denial of service (out-of-bounds read and application crash) via a non-UTF-8 attribute value, related to serialization.
- CVE-2016-4449High
CVE-2016-4449 describes an XXE vulnerability in the xmlStringLenDecodeEntities function in parser.c in libxml2 before version 2.9.4. This vulnerability, when not in validating mode, allows attackers to read arbitrary files or cause denial of service through unspecified vectors.
- CVE-2016-4447High
The xmlParseElementDecl function in libxml2 before version 2.9.4 allows context-dependent attackers to cause a denial of service via a crafted file, resulting in heap-based buffer underread and application crash.
- CVE-2016-1840High
Heap-based buffer overflow in the xmlFAParsePosCharGroup function in libxml2 before version 2.9.4 allows remote attackers to execute arbitrary code or cause a denial of service via a crafted XML document.
- CVE-2016-1835High
Use-after-free vulnerability in the xmlSAX2AttributeNs function in libxml2 before version 2.9.4, as used in Apple iOS before 9.3.2 and OS X before 10.11.5, allows remote attackers to cause a denial of service via a crafted XML document.
- CVE-2016-1834High
Heap-based buffer overflow in the xmlStrncat function in libxml2 before version 2.9.4, used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted XML document.
- CVE-2016-3705High
The xmlParserEntityCheck and xmlParseAttValueComplex functions in libxml2 2.9.3 do not properly keep track of the recursion depth, allowing context-dependent attackers to cause a denial of service via a crafted XML document containing a large number of nested entity references.
- CVE-2016-3627High
The xmlStringGetNodeList function in libxml2 version 2.9.3 and earlier, when used in recovery mode, allows context-dependent attackers to cause a denial of service through a crafted XML document, leading to infinite recursion, stack consumption, and application crash.
Original NVD description (English source)
libxml2 is vulnerable to multiple stack-based buffer overflows in the xmlcatalog utility when running in --shell mode. The usershell() function processes user input using fixed-size stack buffers without proper bounds checking. By supplying an overly long input line, an attacker can overflow internal buffers (command, arg, and argv) during input parsing. This results in memory corruption within the stack frame. Successful exploitation may cause a crash or potentially allow arbitrary code execution in the context of the xmlcatalog process. This issue has been fixed in the commit c2e233fc. NOTE: The maintainers of this project did not agree that this issue is a vulnerability and considered it a bug.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS