Description
libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c. XML_ParseBuffer advances the parse buffer end with parser->m_bufferEnd += len using a caller-supplied length that is not validated against the allocated buffer size, so repeated XML_ParseBuffer calls move m_bufferEnd past the end of the heap allocation and subsequent parsing reads out of bounds. Reaching this path requires a parse buffer to already be present; otherwise XML_ParseBuffer returns XML_ERROR_NO_BUFFER. A buffer is present after a prior call to XML_GetBuffer, either directly (the common case) or indirectly through a prior XML_Parse call that allocates the buffer internally. The over-read discloses adjacent heap memory to the calling application, recovering heap pointers, libc function pointers, and code pointers sufficient to defeat ASLR and build further exploitation primitives.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| libexpat | libexpat | ≤ 2.8.5 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | expat | 2.9.0-1 | — |
| Debian 13 | expat | 2.9.0-1~deb13u1 | — |
| Debian 12 | expat | 2.5.0-1+deb12u5 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | tdom +6 | No fix yet | — |
| Ubuntu 26.04 LTS | tdom +5 | No fix yet | — |
| Ubuntu 24.04 LTS | tdom +4 | No fix yet | — |
| Ubuntu 22.04 LTS | tdom +5 | No fix yet | — |
| Ubuntu 20.04 LTS | tdom +4 | No fix yet | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | gdcm +7 | No fix yet | — |
| Ubuntu 16.04 LTS | gdcm +6 | No fix yet | — |
| Ubuntu Pro 26.04 LTS | swish-e | No fix yet | — |
| Ubuntu Pro 24.04 LTS | swish-e +2 | No fix yet | — |
| Ubuntu Pro 22.04 LTS | swish-e +2 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | expat +3 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | coin3 +4 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | vtk +8 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | vtk +4 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | expat +1 | 2.7.3-1.el10_2.7 | RHSA-2026:98582, RHSA-2026:88248 |
| RHEL 10 | firefox | 153.5.0-1.el10_2 | RHSA-2026:89758 |
| RHEL 9 | expat +1 | 2.5.0-6.el9_8.7 | RHSA-2026:98478, RHSA-2026:88247 |
| RHEL 8 | expat +1 | 2.5.0-6.el8_10 | RHSA-2026:92323 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | expat +2 | 2.8.5-1.2.hum1 | RHSA-2026:85985, RHSA-2026:77959 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | expat | 2.7.3-1.el10_2.7 | ALSA-2026:88248 |
| AlmaLinux 10 | firefox | 153.5.0-1.el10_2 | ALSA-2026:89758 |
| AlmaLinux 9 | expat +1 | 2.5.0-6.el9_8.7 | ALSA-2026:88247 |
| AlmaLinux 8 | expat +1 | 2.5.0-6.el8_10 | ALSA-2026:92323 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | expat | 2.7.3-1.el10_2.7 | RLSA-2026:98582, RLSA-2026:88248 |
| Rocky Linux 10 | expat-devel | 2.7.3-2.el10_3.4 | RLSA-2026:98582 |
| Rocky Linux 10 | firefox | 153.5.0-1.el10_2 | RLSA-2026:89758 |
| Rocky Linux 9 | expat | 2.5.0-6.el9_8.7 | RLSA-2026:98478, RLSA-2026:88247 |
| Rocky Linux 9 | expat-devel | 2.5.0-9.el9_9.4 | RLSA-2026:98478 |
| Rocky Linux 8 | expat | 2.5.0-6.el8_10 | RLSA-2026:92323 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | expat | 2.8.5-150700.3.15.1 | SUSE-SU-2026:4619-1 |
| SLES 15 SP6 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLES 15 SP5 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLES 15 SP4 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLES 12 SP5 | expat | 2.8.5-21.55.1 | SUSE-SU-2026:4615-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | expat | 2.8.5-160000.1.1 | SUSE-SU-2026:24469-1 |
| SLES for SAP 15 SP6 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLES for SAP 15 SP5 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLES for SAP 15 SP4 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLES 16.0 | expat | 2.8.5-160000.1.1 | SUSE-SU-2026:24469-1 |
| SLE Micro 6.2 | expat | 2.8.5-160000.1.1 | SUSE-SU-2026:24460-1 |
| SLE Micro 6.1 | expat | 2.8.5-slfo.1.1_1.1 | SUSE-SU-2026:24554-1 |
| SLE Micro 6.0 | expat | 2.8.5-159998.1.1 | SUSE-SU-2026:24323-1 |
| SLE Micro 5.5 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLE Micro 5.4 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLE Micro 5.3 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLE HPC 15 SP5 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
| SLE HPC 15 SP4 | expat | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | expat | 2.9.0-1.1 | openSUSE-SU-2026:12100-1 |
| openSUSE Leap 16.0 | expat | 2.8.5-160000.1.1 | openSUSE-SU-2026:22177-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | expat | 2.9.0-r0 | — |
| Alpine v3.23 | expat | 2.9.0-r0 | — |
| Alpine v3.22 | expat | 2.9.0-r0 | — |
| Alpine v3.21 | expat | 2.9.0-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | cmake | No fix yet | — |
| Azure Linux 3 | expat | 2.9.0-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | expat +1 | 2.7.3-1.el10_2.7 | ELSA-2026-88248 |
| Oracle Linux 10 | firefox | 153.5.0-1.0.1.el10_2 | ELSA-2026-89758 |
| Oracle Linux 9 | expat +1 | 2.5.0-6.el9_8.7 | ELSA-2026-88247 |
| Oracle Linux 8 | expat +1 | 2.5.0-6.el8_10 | ELSA-2026-92323 |
Advisories 33
- RHSA-2026:88247 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:98478 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:89758 Red Hat Security Advisory: firefox security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:98582 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:88248 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:92323 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RHSA-2026:85985 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- RLSA-2026:98582 Important: expat security update Rocky Linux Security Advisories · Nov 13, 2026
- RLSA-2026:98478 Important: expat security update Rocky Linux Security Advisories · Nov 13, 2026
- WID-SEC-2026-3796 expat: Schwachstelle ermöglicht Offenlegung von Informationen BSI CERT-Bund (WID) · Nov 12, 2026
- SSA-457936 SSA-457936: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.7 Siemens ProductCERT · Nov 10, 2026
- SUSE-SU-2026:24554-1 Security update for expat SUSE / openSUSE Security Updates · Nov 7, 2026
- SUSE-SU-2026:24469-1 Security update for expat SUSE / openSUSE Security Updates · Nov 4, 2026
- ALSA-2026:89758 Important: firefox security, bug fix, and enhancement update AlmaLinux Security Advisories · Nov 4, 2026
- SUSE-SU-2026:24460-1 Security update for expat SUSE / openSUSE Security Updates · Nov 2, 2026
- openSUSE-SU-2026:22177-1 Security update for expat SUSE / openSUSE Security Updates · Nov 1, 2026
- RLSA-2026:89758 Important: firefox security, bug fix, and enhancement update Rocky Linux Security Advisories · Oct 31, 2026
- RLSA-2026:92323 Important: expat security update Rocky Linux Security Advisories · Oct 30, 2026
- ALSA-2026:88247 Important: expat security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:88248 Important: expat security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:92323 Important: expat security update AlmaLinux Security Advisories · Oct 29, 2026
- ELSA-2026-92323 Important: expat security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Oct 29, 2026
- SUSE-SU-2026:24323-1 Security update for expat SUSE / openSUSE Security Updates · Oct 27, 2026
- ELSA-2026-89758 Important: firefox security, bug fix, and enhancement update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Oct 26, 2026
- RLSA-2026:88248 Important: expat security update Rocky Linux Security Advisories · Oct 23, 2026
- RLSA-2026:88247 Important: expat security update Rocky Linux Security Advisories · Oct 23, 2026
- ELSA-2026-88248 Important: expat security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Oct 22, 2026
- ELSA-2026-88247 Important: expat security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Oct 22, 2026
- SUSE-SU-2026:4619-1 Security update for expat SUSE / openSUSE Security Updates · Oct 19, 2026
- RHSA-2026:77959 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- SUSE-SU-2026:4623-1 Security update for expat SUSE / openSUSE Security Updates · Oct 13, 2026
- SUSE-SU-2026:4615-1 Security update for expat SUSE / openSUSE Security Updates · Oct 13, 2026
- openSUSE-SU-2026:12100-1 expat-2.9.0-1.1 on GA media SUSE / openSUSE Security Updates · Oct 11, 2026
References
- Pull Request issue-tracking patch
- Patch Commit patch
- https://www.vulncheck.com/advisories/libexpat-heap-buffer-over-read-in-xmlparse-c-via-xml-parsebuffer third-party-advisory