Description
libexpat in Expat before 2.7.2 allows attackers to trigger large dynamic memory allocations via a small document that is submitted for parsing.
Affected products
libexpat_project: libexpat
References9
- github.com/libexpat/libexpat/issues/1018 ExploitIssue Tracking
- issues.oss-fuzz.com/issues/439133977 ExploitIssue Tracking
- github.com/libexpat/libexpat/blob/676a4c531ec768732fac215da9730… Product
- github.com/libexpat/libexpat/blob/R_2_7_2/expat/Changes Product
- github.com/libexpat/libexpat/pull/1034 Issue Tracking
- www.openwall.com/lists/oss-security/2025/09/16/2
- www.openwall.com/lists/oss-security/2026/05/01/5
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- cert-portal.siemens.com/productcert/html/ssa-089022.html
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 72 · as of 8 November 2026
- CWE
- CWE-770
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.