CVE catalog
CVE-2026-76957
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.
- Severity
- High · CVSS 8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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 - Published
- Updated
- Source
- [NVD] · [CVE record]
- EPSS
- 0.11% · Oct 22, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | expat | sid | 2.9.0-1 | fixed |
| Debian | expat | forky | 2.9.0-1 | fixed |
| Debian | expat | trixie | 2.8.3-1~deb13u1 | vulnerable |
| Debian | expat | trixie-security | 2.9.0-1~deb13u1 | fixed |
| Debian | expat | bookworm | 2.5.0-1+deb12u2 | vulnerable |
| Debian | expat | bookworm-security | 2.5.0-1+deb12u5 | fixed |
| Cpe | libexpat | Not reported | 2.8.4 | fixed |
| Ubuntu | expat | noble | 2.6.1-2ubuntu0.6 | fixed |
| Ubuntu | libexpat1 | noble | 2.6.1-2ubuntu0.6 | fixed |
| Ubuntu | libexpat1-dev | noble | 2.6.1-2ubuntu0.6 | fixed |
| Suse | expat | linux enterprise module for basesystem 15 sp7 | 2.8.5-150700.3.15.1 | fixed |
| Suse | expat | linux enterprise micro 5.3 | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise micro 5.4 | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise micro 5.5 | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise high performance computing 15 sp4-espos | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise high performance computing 15 sp4-ltss | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise high performance computing 15 sp5-espos | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise high performance computing 15 sp5-ltss | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise server 15 sp4-ltss | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise server 15 sp5-ltss | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise server 15 sp6-ltss | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise server for sap applications 15 sp4 | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise server for sap applications 15 sp5 | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise server for sap applications 15 sp6 | 2.8.5-150400.3.40.1 | fixed |
| Suse | expat | linux enterprise server 12 sp5-ltss | 2.8.5-21.55.1 | fixed |
| Suse | expat | linux enterprise server ltss extended security 12 sp5 | 2.8.5-21.55.1 | fixed |
| Alpine | expat | 3.21 | 2.8.4-r0 | fixed |
| Alpine | expat | 3.22 | 2.8.4-r0 | fixed |
| Alpine | expat | 3.23 | 2.8.4-r0 | fixed |
| Alpine | expat | 3.24 | 2.8.4-r0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | expat | source | sid | 2.8.4-1 | not yet assigned | Not reported | [1144927] |
| Debian | expat | source | forky | 2.8.4-1 | not yet assigned | Not reported | [1144927] |
| Debian | expat | source | trixie | 2.9.0-1~deb13u1 | not yet assigned | Not reported | [1144927] |
| Debian | expat | source | bookworm | 2.5.0-1+deb12u3 | not yet assigned | Not reported | [1144927] |
| Cpe | libexpat | cpe | Not reported | 2.8.4 | Not reported | NVD-CVE-2026-76957 | Not reported |
| Ubuntu | expat | deb | noble | 2.6.1-2ubuntu0.6 | Not reported | Not reported | Not reported |
| Ubuntu | libexpat1 | deb | noble | 2.6.1-2ubuntu0.6 | Not reported | Not reported | Not reported |
| Ubuntu | libexpat1-dev | deb | noble | 2.6.1-2ubuntu0.6 | Not reported | Not reported | Not reported |
| Suse | expat | rpm | linux enterprise module for basesystem 15 sp7 | 2.8.5-150700.3.15.1 | Not reported | SUSE-SU-2026:4619-1 | Not reported |
| Suse | expat | rpm | linux enterprise micro 5.3 | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise micro 5.4 | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise micro 5.5 | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise high performance computing 15 sp4-espos | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise high performance computing 15 sp4-ltss | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise high performance computing 15 sp5-espos | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise high performance computing 15 sp5-ltss | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise server 15 sp4-ltss | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise server 15 sp5-ltss | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise server 15 sp6-ltss | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise server for sap applications 15 sp4 | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise server for sap applications 15 sp5 | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise server for sap applications 15 sp6 | 2.8.5-150400.3.40.1 | Not reported | SUSE-SU-2026:4623-1 | Not reported |
| Suse | expat | rpm | linux enterprise server 12 sp5-ltss | 2.8.5-21.55.1 | Not reported | SUSE-SU-2026:4615-1 | Not reported |
| Suse | expat | rpm | linux enterprise server ltss extended security 12 sp5 | 2.8.5-21.55.1 | Not reported | SUSE-SU-2026:4615-1 | Not reported |
| Alpine | expat | apk | 3.21 | 2.8.4-r0 | Not reported | ALPINE-CVE-2026-76957 | Not reported |
| Alpine | expat | apk | 3.22 | 2.8.4-r0 | Not reported | ALPINE-CVE-2026-76957 | Not reported |
| Alpine | expat | apk | 3.23 | 2.8.4-r0 | Not reported | ALPINE-CVE-2026-76957 | Not reported |
| Alpine | expat | apk | 3.24 | 2.8.4-r0 | Not reported | ALPINE-CVE-2026-76957 | Not reported |
OpenFactory catalog packages
Matching against OpenFactory catalog package versions is in progress.
[Debian 12 (Bookworm)]
- [expat]Unknown
Details (4)
2.5.0-1+deb12u2· amd64 · bookwormAffected · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u2· arm64 · bookwormAffected · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u3· amd64 · bookworm-securityFixed · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u3· arm64 · bookworm-securityFixed · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
- [libexpat1]Unknown
Source package: [expat]
Details (4)
2.5.0-1+deb12u2· amd64 · bookwormAffected · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u2· arm64 · bookwormAffected · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u3· amd64 · bookworm-securityFixed · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u3· arm64 · bookworm-securityFixed · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
- [libexpat1-dev]Unknown
Source package: [expat]
Details (4)
2.5.0-1+deb12u2· amd64 · bookwormAffected · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u2· arm64 · bookwormAffected · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u3· amd64 · bookworm-securityFixed · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
2.5.0-1+deb12u3· arm64 · bookworm-securityFixed · Fixed:
2.5.0-1+deb12u3nvd · expat · debian · bookworm
Observed:
References
- [https://access.redhat.com/errata/RHSA-2026:60451]
- [https://ftp.suse.com/pub/projects/security/csaf/suse-su-2026_4619-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-76957]
- [https://osv.dev/vulnerability/ALPINE-CVE-2026-76957]
- [https://osv.dev/vulnerability/SUSE-SU-2026:4615-1]
- [https://osv.dev/vulnerability/SUSE-SU-2026:4619-1]
- [https://osv.dev/vulnerability/SUSE-SU-2026:4623-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-76957]
- [https://ubuntu.com/security/notices/USN-8813-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2930.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]