CVEvulnerability
CVE-2026-93990
8.7 HIGH
Official page ↗
- Status
- Awaiting Analysis
- Published
- 2026-09-19
- Last modified
- 2026-09-28
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 8.7 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Weaknesses
- CWE-176
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.
Related
Weakness · CWE (1)
- CWE-176 Improper Handling of Unicode Encoding weakness
References
- https://blog.hartwork.org/posts/expat-2-8-5-released/ blog.hartwork.org
- https://github.com/libexpat/libexpat github.com
- https://github.com/libexpat/libexpat/commit/ff6e1d7e750bbe245178f51a47a965dc8342861a github.com
- https://github.com/libexpat/libexpat/pull/1282 github.com
- https://github.com/libexpat/libexpat/releases/tag/R_2_8_5 github.com
- https://www.vulncheck.com/advisories/expat-through-2.8.4-malformed-utf-16-acceptance-via-unchecked-surrogate www.vulncheck.com