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libexpat — security advisories

17 advisories2 sourceslatest 2026-08-24⚡ RSS feed

Every advisory CSIRTS.com has correlated to libexpat, newest first — across national CERTs, vendor PSIRTs and vulnerability databases.

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[UPDATE] [medium] libexpat: Multiple vulnerabilities allow unspecified attack

mediumCVE-2026-50219 CVE-2026-56403 CVE-2026-56404 CVE-2026-56405cert-bund2026-08-24

CVE-2026-72522: libexpat before 2.8.3 has an out-of-bounds read and resultant infinite loop because low surrogates are treated the same as high surrogates during Unicode processing in the *_toUtf16 functions.

mediumCVSS 6.2CVE-2026-72522msrc2026-08-11

CVE-2026-76956: In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content.

highCVSS 7.5CVE-2026-76956msrc2026-08-11

CVE-2026-76957: libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.

mediumCVSS 4.9CVE-2026-76957msrc2026-08-11

[UPDATE] [low] libexpat: Multiple vulnerabilities allow denial of service

lowCVE-2026-32776 CVE-2026-32777 CVE-2026-32778cert-bund2026-07-24

CVE-2026-50219: libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_GetBuffer, XML_Parse, XML_ParseBuffer, XML_ParserFree, or XML_ParserReset from within handlers in cases of a policy violation. Thus, a use-after-free can occur,

mediumCVSS 4.9CVE-2026-50219msrc2026-06-09

CVE-2026-56410: xmlwf in libexpat before 2.8.2 has an integer overflow in resolveSystemId.

mediumCVSS 6.9CVE-2026-56410msrc2026-06-09

CVE-2026-56412: libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.

mediumCVSS 4.9CVE-2026-56412msrc2026-06-09

CVE-2026-56406: libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was present in XML_Parse.

mediumCVSS 6.9CVE-2026-56406msrc2026-06-09

CVE-2026-56132: In libexpat before 2.8.2, there is a heap-based buffer overflow in doProlog in xmlparse.c because scaffold backing array reallocation is mishandled when there is data-structure sharing across parsers.

mediumCVSS 6.9CVE-2026-56132msrc2026-06-09

CVE-2026-56404: libexpat before 2.8.2 has an integer overflow in addBinding.

mediumCVSS 6.9CVE-2026-56404msrc2026-06-09

CVE-2026-56407: libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.

mediumCVSS 6.9CVE-2026-56407msrc2026-06-09

CVE-2026-56403: libexpat before 2.8.2 has an integer overflow in storeAtts.

mediumCVSS 6.9CVE-2026-56403msrc2026-06-09

CVE-2026-56409: xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used.

mediumCVSS 6.5CVE-2026-56409msrc2026-06-09

CVE-2026-56405: libexpat before 2.8.2 has an integer overflow in getAttributeId.

mediumCVSS 6.9CVE-2026-56405msrc2026-06-09

CVE-2026-56411: xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION declarations.

mediumCVSS 6.9CVE-2026-56411msrc2026-06-09

CVE-2026-56131: libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).

mediumCVSS 4.9CVE-2026-56131msrc2026-06-09