CVE-2026-124317
libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16
CVSS Score
4.8
EPSS Score
0.0%
EPSS Percentile
0th
libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.
| CWE | CWE-126 |
| Vendor | libexpat |
| Product | libexpat |
| Published | Nov 7, 2026 |
Stay Ahead of the Next One
Get instant alerts for libexpat libexpat
Be the first to know when new medium vulnerabilities affecting libexpat libexpat are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low
Affected Versions
libexpat / libexpat
0 ≤ 2.10.0
References
github.com: https://github.com/libexpat/libexpat/pull/1492 github.com: https://github.com/libexpat/libexpat/blob/a70841d9ffa64ddde29ab824ed6305035ebe4c47/expat/lib/xmltok.c#L1274-L1322 github.com: https://github.com/libexpat/libexpat vulncheck.com: https://www.vulncheck.com/advisories/libexpat-through-2.10.0-out-of-bounds-read-via-unknown-toutf8-and-unknown-toutf16
Credits
Oğuzhan Demirbaş Sebastian Pipping