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Out-of-bounds Read The advisory has been revoked - it doesn't affect any version of package expat-devel  (opens in a new tab)

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EPSS
0.55% (45th percentile)

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  • Snyk IDSNYK-RHEL10-EXPATDEVEL-20566739
  • published8 Oct 2026
  • disclosed7 Oct 2026
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Introduced: 7 Oct 2026

NewCVE-2026-77214  (opens in a new tab)
CWE-125  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream expat-devel package and not the expat-devel package as distributed by RHEL.

libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c. XML_ParseBuffer advances the parse buffer end with parser->m_bufferEnd += len using a caller-supplied length that is not validated against the allocated buffer size, so repeated XML_ParseBuffer calls move m_bufferEnd past the end of the heap allocation and subsequent parsing reads out of bounds. Reaching this path requires a parse buffer to already be present; otherwise XML_ParseBuffer returns XML_ERROR_NO_BUFFER. A buffer is present after a prior call to XML_GetBuffer, either directly (the common case) or indirectly through a prior XML_Parse call that allocates the buffer internally. The over-read discloses adjacent heap memory to the calling application, recovering heap pointers, libc function pointers, and code pointers sufficient to defeat ASLR and build further exploitation primitives.