CVE-2026-72522

EUVD-2026-54990
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mitreCNA
6.2 MEDIUM
LOCAL
LOW
NONE
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 4.97%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
libexpat_projectlibexpat
𝑥
< 2.8.3
CNA
Debian logo
Debian Releases
Debian Product
Codename
expat
bookworm
vulnerable
bookworm (security)
vulnerable
bullseye
vulnerable
bullseye (security)
vulnerable
forky
vulnerable
sid
vulnerable
trixie
vulnerable
trixie (security)
vulnerable
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://bugzilla.mozilla.org/show_bug.cgi?id=2053153
https://github.com/libexpat/libexpat/pull/1296