Description
When an Expat parser with a registered ElementDeclHandler parses an inline
document type definition containing a deeply nested content model a C stack
overflow occurs.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Python Software Foundation | CPython | < 3.10.21, 3.11.0 – < 3.11.16, 3.12.0 – < 3.12.14, 3.13.0 – < 3.13.13, 3.14.0 – < 3.14.4, 3.15.0a1 – < 3.15.0a8 | 3.10.21 |
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 | python3.14 | 3.14.3-4 | — |
| Debian 13 | python3.13 | 3.13.5-2+deb13u2 | — |
| Debian 12 | python3.11 | 3.11.2-6+deb12u8 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | pypy3 | No fix yet | — |
| Ubuntu 26.04 LTS | pypy3 | No fix yet | — |
| Ubuntu 26.04 LTS | python3.14 | 3.14.4-1ubuntu0.1 | USN-8744-1, USN-8509-1 |
| Ubuntu 25.10 | pypy3 +2 | No fix yet | — |
| Ubuntu 24.04 LTS | pypy3 | No fix yet | — |
| Ubuntu 24.04 LTS | python3.12 | 3.12.3-1ubuntu0.15 | USN-8744-1, USN-8509-1 |
| Ubuntu 22.04 LTS | pypy3 | No fix yet | — |
| Ubuntu 22.04 LTS | python3.10 | 3.10.12-1~22.04.16 | USN-8744-1, USN-8509-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | pypy3 | No fix yet | — |
| Ubuntu Pro 22.04 LTS | python2.7 | 2.7.18-13ubuntu1.5+esm9 | USN-8744-1 |
| Ubuntu Pro 22.04 LTS | python3.11 | 3.11.0~rc1-1~22.04.1+esm2 | USN-8744-1 |
| Ubuntu Pro 20.04 LTS | python2.7 | 2.7.18-1~20.04.7+esm10 | USN-8744-1 |
| Ubuntu Pro 20.04 LTS | python3.8 | 3.8.10-0ubuntu1~20.04.18+esm7 | USN-8744-1 |
| Ubuntu Pro 20.04 LTS | python3.9 | 3.9.5-3ubuntu0~20.04.1+esm11 | USN-8744-1 |
| Ubuntu Pro 18.04 LTS | python2.7 | 2.7.17-1~18.04ubuntu1.13+esm15 | USN-8744-1 |
| Ubuntu Pro 18.04 LTS | python3.6 | 3.6.9-1~18.04ubuntu1.13+esm10 | USN-8744-1 |
| Ubuntu Pro 18.04 LTS | python3.7 | 3.7.5-2ubuntu1~18.04.2+esm11 | USN-8744-1 |
| Ubuntu Pro 18.04 LTS | python3.8 | 3.8.0-3ubuntu1~18.04.2+esm11 | USN-8744-1 |
| Ubuntu Pro 16.04 LTS | python2.7 | 2.7.12-1ubuntu0~16.04.18+esm22 | USN-8744-1 |
| Ubuntu Pro 16.04 LTS | python3.5 | 3.5.2-2ubuntu0~16.04.13+esm25 | USN-8744-1 |
| Ubuntu Pro 14.04 LTS | python2.7 | 2.7.6-8ubuntu0.6+esm30 | USN-8744-1 |
| Ubuntu Pro 14.04 LTS | python3.4 | 3.4.3-1ubuntu1~14.04.7+esm21 | USN-8744-1 |
| Ubuntu Pro 14.04 LTS | python3.5 | 3.5.2-2ubuntu0~16.04.4~14.04.1+esm11 | USN-8744-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | python3 +8 | 3.12.13-2.el10_2 | RHSA-2026:19064 |
| RHEL 10 | python3.14 +13 | 3.14.4-2.el10_2 | RHSA-2026:19019 |
| RHEL 9 | python3.12 +6 | 3.12.13-2.el9_8 | RHSA-2026:19177 |
| RHEL 9 | python3.14 +13 | 3.14.4-2.el9_8 | RHSA-2026:19176 |
| RHEL 8 | python3.12 +7 | 3.12.13-2.el8_10 | RHSA-2026:10950 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | python3 +15 | 3.14.4-1.hum1 | RHSA-2026:7661 |
| Red Hat Hardened Images 1 | python3.11 +6 | 3.11.15-4.hum1 | RHSA-2026:8822 |
| Red Hat Hardened Images 1 | python3.12 +6 | 3.12.13-3.hum1 | RHSA-2026:8824 |
| Red Hat Hardened Images 1 | python3.13 +8 | 3.13.13-1.hum1 | RHSA-2026:7443 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | python3 +7 | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux 10 | python3.14 +13 | 3.14.4-2.el10_2 | ALSA-2026:19019 |
| AlmaLinux 9 | python3.12 +6 | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| AlmaLinux 9 | python3.14 +13 | 3.14.4-2.el9_8 | ALSA-2026:19176 |
| AlmaLinux 8 | python3.12 +7 | 3.12.13-2.el8_10 | ALSA-2026:10950 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | python3.12 | 3.12.13-2.el10_2 | RLSA-2026:19064 |
| Rocky Linux 10 | python3.14 | 3.14.4-2.el10_2 | RLSA-2026:19019 |
| Rocky Linux 9 | python3.12 | 3.12.13-2.el9_8 | RLSA-2026:19177 |
| Rocky Linux 9 | python3.14 | 3.14.4-2.el9_8 | RLSA-2026:19176 |
| Rocky Linux 8 | python3.12 | 3.12.13-2.el8_10 | RLSA-2026:10950 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | python +1 | 2.7.18-150000.111.1 | SUSE-SU-2026:1206-1 |
| SLES 15 SP7 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLES 15 SP7 | python311-core | 3.11.15-150600.3.53.1 | SUSE-SU-2026:1349-1 |
| SLES 15 SP6 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLES 15 SP6 | python311 +1 | 3.11.15-150600.3.53.1 | SUSE-SU-2026:1349-1 |
| SLES 15 SP6 | python312 +1 | 3.12.13-150600.3.53.1 | SUSE-SU-2026:4534-1, SUSE-SU-2026:1292-1 |
| SLES 15 SP5 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLES 15 SP5 | python311 +2 | 3.11.15-150400.9.85.1 | SUSE-SU-2026:1530-1 |
| SLES 15 SP5 | python39 +1 | 3.9.25-150300.4.99.1 | SUSE-SU-2026:1296-1 |
| SLES 15 SP4 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLES 15 SP4 | python310 +1 | 3.10.20-150400.4.107.1 | SUSE-SU-2026:1376-1 |
| SLES 15 SP4 | python311 +2 | 3.11.15-150400.9.85.1 | SUSE-SU-2026:1530-1 |
| SLES 12 SP5 | python +2 | 2.7.18-33.74.1 | SUSE-SU-2026:1417-1 |
| SLES 12 SP5 | python3 +1 | 3.4.10-25.180.1 | SUSE-SU-2026:1385-1 |
| SLES 12 SP5 | python36 +1 | 3.6.15-108.1 | SUSE-SU-2026:4743-1, SUSE-SU-2026:1345-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 3 | python311 +1 | 3.11.15-150600.3.53.1 | SUSE-SU-2026:1349-1 |
| SLES 3 | python313 +1 | 3.13.13-150700.4.45.1 | SUSE-SU-2026:1354-1 |
| SLES for SAP 16.0 | python313 +2 | 3.13.13-160000.1.1 | SUSE-SU-2026:21178-1 |
| SLES for SAP 15 SP6 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLES for SAP 15 SP6 | python311 +1 | 3.11.15-150600.3.53.1 | SUSE-SU-2026:1349-1 |
| SLES for SAP 15 SP6 | python312 +1 | 3.12.13-150600.3.53.1 | SUSE-SU-2026:4534-1, SUSE-SU-2026:1292-1 |
| SLES for SAP 15 SP5 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLES for SAP 15 SP5 | python311 +2 | 3.11.15-150400.9.85.1 | SUSE-SU-2026:1530-1 |
| SLES for SAP 15 SP5 | python39 +1 | 3.9.25-150300.4.99.1 | SUSE-SU-2026:1296-1 |
| SLES for SAP 15 SP4 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLES for SAP 15 SP4 | python310 +1 | 3.10.20-150400.4.107.1 | SUSE-SU-2026:1376-1 |
| SLES for SAP 15 SP4 | python311 +2 | 3.11.15-150400.9.85.1 | SUSE-SU-2026:1530-1 |
| SLES 16.0 | python313 +2 | 3.13.13-160000.1.1 | SUSE-SU-2026:21178-1 |
| SLE Micro 6.2 | python313 +1 | 3.13.13-160000.1.1 | SUSE-SU-2026:21104-1 |
| SLE Micro 6.1 | python311 +1 | 3.11.15-slfo.1.1_3.1 | SUSE-SU-2026:23743-1, SUSE-SU-2026:21254-1 |
| SLE Micro 5.5 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLE Micro 5.4 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLE Micro 5.3 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLE HPC 15 SP5 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLE HPC 15 SP5 | python311 +2 | 3.11.15-150400.9.85.1 | SUSE-SU-2026:1530-1 |
| SLE HPC 15 SP4 | python3 +1 | 3.6.15-150300.10.129.1 | SUSE-SU-2026:4754-1 |
| SLE HPC 15 SP4 | python310 +1 | 3.10.20-150400.4.107.1 | SUSE-SU-2026:1376-1 |
| SLE HPC 15 SP4 | python311 +2 | 3.11.15-150400.9.85.1 | SUSE-SU-2026:1530-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python310 | 3.10.20-3.1 | openSUSE-SU-2026:10477-1 |
| openSUSE Tumbleweed | python311 | 3.11.15-4.1 | openSUSE-SU-2026:10478-1 |
| openSUSE Tumbleweed | python312 | 3.12.13-4.1 | openSUSE-SU-2026:10479-1 |
| openSUSE Tumbleweed | python313 | 3.13.12-3.1 | openSUSE-SU-2026:10480-1 |
| openSUSE Tumbleweed | python314 | 3.14.3-4.1 | openSUSE-SU-2026:10481-1 |
| openSUSE Tumbleweed | python315 | 3.15.0~a7-3.1 | openSUSE-SU-2026:10469-1 |
| openSUSE Leap 16.0 | python313 +4 | 3.13.13-160000.1.1 | openSUSE-SU-2026:20517-1 |
| openSUSE Leap 15.6 | python +2 | 2.7.18-150000.111.1 | SUSE-SU-2026:1206-1 |
| openSUSE Leap 15.6 | python310 +2 | 3.10.20-150400.4.107.1 | SUSE-SU-2026:1376-1 |
| openSUSE Leap 15.6 | python311 +2 | 3.11.15-150600.3.53.1 | SUSE-SU-2026:1349-1 |
| openSUSE Leap 15.6 | python312 +2 | 3.12.13-150600.3.53.1 | SUSE-SU-2026:1292-1 |
| openSUSE Leap 15.6 | python39 +2 | 3.9.25-150300.4.99.1 | SUSE-SU-2026:1296-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | python3 | 3.14.5-r0 | — |
| Alpine v3.23 | python3 | 3.12.14-r0 | — |
| Alpine v3.22 | python3 | 3.12.14-r0 | — |
| Alpine v3.21 | python3 | 3.12.14-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | python3 +7 | 3.9.25-1.amzn2023.0.4 | ALAS2023-2026-1583 |
| Amazon Linux 2023 | python3.11 +6 | 3.11.15-1.amzn2023.0.1 | ALAS2023-2026-1620 |
| Amazon Linux 2023 | python3.12 +6 | 3.12.13-2.amzn2023.0.1 | ALAS2023-2026-1619 |
| Amazon Linux 2023 | python3.13 +8 | 3.13.13-1.amzn2023.0.1 | ALAS2023-2026-1600 |
| Amazon Linux 2023 | python3.14 +13 | 3.14.3-2.amzn2023.0.1 | ALAS2023-2026-1617 |
| Amazon Linux 2 | python +6 | 2.7.18-1.amzn2.0.17 | ALAS2-2026-3218 |
| Amazon Linux 2 | python3 +6 | 3.7.16-1.amzn2.0.24 | ALAS2-2026-3217 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | python-py | No fix yet | — |
| Azure Linux 3 | python3 | 3.12.14-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | python3 +7 | 3.12.13-2.0.1.el10_2 | ELSA-2026-19064 |
| Oracle Linux 10 | python3.14 +13 | 3.14.4-2.el10_2 | ELSA-2026-19019 |
| Oracle Linux 9 | python3.12 +6 | 3.12.13-2.0.1.el9_8 | ELSA-2026-19177 |
| Oracle Linux 9 | python3.14 +13 | 3.14.4-2.el9_8 | ELSA-2026-19176 |
| Oracle Linux 8 | python3.12 +7 | 3.12.13-2.el8_10 | ELSA-2026-10950 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | python-3.10 | 3.10.21-r6 | — |
| Wolfi rolling | python-3.11 | 3.11.15-r9 | — |
| Wolfi rolling | python-3.12 | 3.12.14-r8 | — |
| Wolfi rolling | python-3.13 | 3.13.12-r7 | — |
| Wolfi rolling | python-3.14 | 3.14.3-r6 | — |
Advisories 50
- ALSA-2026:19176 Important: python3.14 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:19177 Important: python3.12 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:19064 Important: python3.12 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:19019 Important: python3.14 security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:10950 Important: python3.12 security update AlmaLinux Security Advisories · Oct 29, 2026
- SUSE-SU-2026:4754-1 Security update for python3 SUSE / openSUSE Security Updates · Oct 21, 2026
- WID-SEC-2026-0741 CPython: Mehrere Schwachstellen ermöglichen Manipulation von Dateien und DoS BSI CERT-Bund (WID) · Oct 20, 2026
- SUSE-SU-2026:4743-1 Security update for python36 SUSE / openSUSE Security Updates · Oct 20, 2026
- RHSA-2026:8822 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:8824 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:19177 Red Hat Security Advisory: python3.12 security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:19176 Red Hat Security Advisory: python3.14 security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:19064 Red Hat Security Advisory: python3.12 security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:19019 Red Hat Security Advisory: python3.14 security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:10950 Red Hat Security Advisory: python3.12 security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:7661 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:7443 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- SUSE-SU-2026:4534-1 Security update for python312 SUSE / openSUSE Security Updates · Oct 6, 2026
- SUSE-SU-2026:23743-1 Security update for python311 SUSE / openSUSE Security Updates · Sep 27, 2026
- USN-8744-1 python2.7, python3.4, python3.5, python3.6, python3.7, python3.8, python3.9, python3.10, python3.11, python3.12, python3.14 vulnerabilities Ubuntu Security Notices (USN) · Sep 15, 2026
- VDE-2026-088 METTLER TOLEDO: LabX Standard and Enterprise Report on External Component Analysis - v21.4 CERT@VDE · Sep 10, 2026
- ELSA-2026-19019 Important: python3.14 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 8, 2026
- ELSA-2026-19064 Important: python3.12 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 8, 2026
- USN-8509-1 python3.10, python3.12, python3.14 vulnerabilities Ubuntu Security Notices (USN) · Jul 6, 2026
- ELSA-2026-19177 Important: python3.12 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 12, 2026
- ELSA-2026-19176 Important: python3.14 security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 12, 2026
- RLSA-2026:19176 Important: python3.14 security update Rocky Linux Security Advisories · May 30, 2026
- RLSA-2026:19019 Important: python3.14 security update Rocky Linux Security Advisories · May 29, 2026
- RLSA-2026:19064 Important: python3.12 security update Rocky Linux Security Advisories · May 29, 2026
- RLSA-2026:19177 Important: python3.12 security update Rocky Linux Security Advisories · May 28, 2026
- ALAS2023-2026-1600 Moderate: python3.13 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 30, 2026
- ALAS2023-2026-1617 Important: python3.14 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 30, 2026
- ALAS2023-2026-1619 Important: python3.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 30, 2026
- ALAS2023-2026-1620 Important: python3.11 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 30, 2026
- RLSA-2026:10950 Important: python3.12 security update Rocky Linux Security Advisories · Apr 28, 2026
- ELSA-2026-10950 Important: python3.12 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 27, 2026
- SUSE-SU-2026:21254-1 Security update for python311 SUSE / openSUSE Security Updates · Apr 24, 2026
- openSUSE-SU-2026:20517-1 Security update for python313 SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:21178-1 Security update for python313 SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:1530-1 Security update for python311 SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:1417-1 Security update for python SUSE / openSUSE Security Updates · Apr 18, 2026
- SUSE-SU-2026:21104-1 Security update for python313 SUSE / openSUSE Security Updates · Apr 17, 2026
- SUSE-SU-2026:1385-1 Security update for python3 SUSE / openSUSE Security Updates · Apr 17, 2026
- SUSE-SU-2026:1376-1 Security update for python310 SUSE / openSUSE Security Updates · Apr 17, 2026
- SUSE-SU-2026:1354-1 Security update for python313 SUSE / openSUSE Security Updates · Apr 16, 2026
- SUSE-SU-2026:1345-1 Security update for python36 SUSE / openSUSE Security Updates · Apr 16, 2026
- SUSE-SU-2026:1349-1 Security update for python311 SUSE / openSUSE Security Updates · Apr 16, 2026
- SUSE-SU-2026:1296-1 Security update for python39 SUSE / openSUSE Security Updates · Apr 14, 2026
- SUSE-SU-2026:1292-1 Security update for python312 SUSE / openSUSE Security Updates · Apr 14, 2026
- ALAS2023-2026-1583 Important: python3.9 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 13, 2026
References
- https://github.com/python/cpython/commit/eb0e8be3a7e11b87d198a2c3af1ed0eccf532768 patch
- https://mail.python.org/archives/list/security-announce@python.org/thread/5M7CGUW3XBRY7II4DK43KF7NQQ3TPZ6R/ vendor-advisory
- https://github.com/python/cpython/issues/145986 issue-tracking
- https://github.com/python/cpython/pull/145987 patch
- https://github.com/python/cpython/commit/196edfb06a7458377d4d0f4b3cd41724c1f3bd4a patch
- https://github.com/python/cpython/commit/e0a8a6da90597a924b300debe045cdb4628ee1f3 patch
- https://github.com/python/cpython/commit/642865ddf4b232da1f3b1f7abcfa3254c4bfe785 patch
- https://github.com/python/cpython/commit/af856a7177326ac25d9f66cc6dd28b554d914fee patch
- https://github.com/python/cpython/commit/24ce88b285f56ee11626cf5e472af3cd8cc7c621 patch