RHSA-2026:98478 - Security Advisory

Topic

An update for expat is now available for Red Hat Enterprise Linux 9.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

Expat is a C library for parsing XML documents.

Security Fix(es):

• expat: Expat: Denial of Service via quadratic complexity in attribute processing (CVE-2026-66046)
• expat: Expat: XML Injection via Malformed UTF-16 Input (CVE-2026-93990)
• expat: expat: Denial of Service via integer overflow in expat_realloc (CVE-2026-102633)
• expat: expat: Information disclosure via heap buffer over-read in XML_ParseBuffer (CVE-2026-77214)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 9 x86_64
• Red Hat Enterprise Linux for IBM z Systems 9 s390x
• Red Hat Enterprise Linux for Power, little endian 9 ppc64le
• Red Hat Enterprise Linux for ARM 64 9 aarch64

Fixes

• BZ - 2517901 - CVE-2026-66046 expat: Expat: Denial of Service via quadratic complexity in attribute processing
• BZ - 2538967 - CVE-2026-93990 expat: Expat: XML Injection via Malformed UTF-16 Input
• BZ - 2543288 - CVE-2026-102633 expat: expat: Denial of Service via integer overflow in expat_realloc
• BZ - 2547476 - CVE-2026-77214 expat: expat: Information disclosure via heap buffer over-read in XML_ParseBuffer

CVEs

• CVE-2026-66046
• CVE-2026-77214
• CVE-2026-93990
• CVE-2026-102633

References

• https://access.redhat.com/security/updates/classification/#important