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Vulnerabilities

Vulnerability · CVE-2026-76957

libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks.

Published Aug 20, 2026 · catalog updated Oct 16, 2026 · libexpat before 2.8.4 lacks

Check if you run it

No confirmed exploitation is on record for CVE-2026-76957. EPSS is 0.11%. Act only if a listed version of libexpat before 2.8.4 lacks is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (libexpat before 2.8.4 lacks).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.11%
Remediation
Advisory link
Affected products
Debian:12 expat · Debian:13 expat · Debian:14 expat

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Debian:12 expat0 → 2.5.0-1+deb12u3
  • Debian:13 expat0 → 2.9.0-1~deb13u1
  • Debian:14 expat0 → 2.8.4-1

How to fix CVE-2026-76957

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-76957. EPSS is 0.11%. Act only if a listed version of libexpat before 2.8.4 lacks is installed.

Which versions are affected?

Compare what you have installed with 0 → 2.5.0-1+deb12u3, 0 → 2.9.0-1~deb13u1, 0 → 2.8.4-1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.11%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Debian security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 20, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    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.

  2. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    expat fixed in 2.5.0-1+deb12u3; expat fixed in 2.9.0-1~deb13u1; expat fixed in 2.8.4-1

  3. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    expat fixed in 2.5.0-1+deb12u3

  4. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    expat fixed in 2.9.0-1~deb13u1

  5. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    expat fixed in 2.8.4-1

  6. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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.

Sources

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.