High severity7.5NVD Advisory· Published Sep 19, 2026· Updated Sep 28, 2026
CVE-2026-93990
CVE-2026-93990
Description
Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing lone high surrogates that consume the following code unit, causing Expat to pass unpaired surrogates to applications built with XML_UNICODE and to silently replace input characters in other builds.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
4- Range: <2.8.5
- osv-coords3 versionspkg:rpm/almalinux/expatpkg:rpm/almalinux/expat-develpkg:rpm/opensuse/expat&distro=openSUSE%20Tumbleweed
< 2.5.0-4.el8_10+ 2 more
- (no CPE)range: < 2.5.0-4.el8_10
- (no CPE)range: < 2.5.0-4.el8_10
- (no CPE)range: < 2.8.5-1.1
Patches
Vulnerability mechanics
References
5- blog.hartwork.org/posts/expat-2-8-5-released/nvd
- github.com/libexpat/libexpat/commit/ff6e1d7e750bbe245178f51a47a965dc8342861anvd
- github.com/libexpat/libexpat/pull/1282nvd
- github.com/libexpat/libexpat/releases/tag/R_2_8_5nvd
- www.vulncheck.com/advisories/expat-through-2.8.4-malformed-utf-16-acceptance-via-unchecked-surrogatenvd
News mentions
0No linked articles in our index yet.