High severity · published Aug 20, 2026
CVE-2026-76957
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks
7.8
CVSS
0.1%
EPSS
No
On KEV
Description
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
libexpat · libexpat project
before 2.8.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-76957
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-76957
Issue Tracking
https://github.com/libexpat/libexpat/pull/1322
Issue Tracking
https://github.com/libexpat/libexpat/pull/1329
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