Description
The XML parser (xmlparse.c) in expat before 2.1.0 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via an XML file with many identifiers with the same value.
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 | 2.1.0~beta3-1 | — |
| Debian 14 | xmlrpc-c | 1.16.33-3.2 | — |
| Debian 13 | expat | 2.1.0~beta3-1 | — |
| Debian 13 | xmlrpc-c | 1.16.33-3.2 | — |
| Debian 12 | expat | 2.1.0~beta3-1 | — |
| Debian 12 | libxmltok | No fix yet | — |
| Debian 12 | xmlrpc-c | 1.16.33-3.2 | — |
| Debian 6.0 | expat | 2.0.1-7+squeeze1 | DSA-2525-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | cadaver +4 | No fix yet | — |
| Ubuntu 26.04 LTS | cadaver +3 | No fix yet | — |
| Ubuntu 25.10 | cadaver +4 | No fix yet | — |
| Ubuntu 24.04 LTS | cadaver +1 | No fix yet | — |
| Ubuntu 22.04 LTS | cadaver +1 | No fix yet | — |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | cadaver +1 | No fix yet | — |
| Ubuntu 18.04 LTS | vnc4 +2 | No fix yet | — |
| Ubuntu 16.04 LTS | cadaver +1 | No fix yet | — |
| Ubuntu Pro 26.04 LTS | swish-e | No fix yet | — |
| Ubuntu Pro 24.04 LTS | swish-e | No fix yet | — |
| Ubuntu Pro 22.04 LTS | swish-e | No fix yet | — |
| Ubuntu Pro 20.04 LTS | swish-e | No fix yet | — |
| Ubuntu Pro 18.04 LTS | coin3 +1 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | vnc4 +5 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | vnc4 +1 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | expat +1 | 2.0.1-11.el6_2 | RHSA-2012:0731 |
| RHEL 5 | expat +1 | 1.95.8-11.el5_8 | RHSA-2012:0731 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES 12 SP5 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES 12 SP4 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES 12 SP4 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES 12 SP3 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES 12 SP3 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES 12 SP2 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES 12 SP2 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES 12 SP1 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES 12 SP1 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES 12 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP5 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP5 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP4 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP4 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP3 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP3 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP2 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP2 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP1 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SLES for SAP 12 SP1 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SUSE OpenStack Cloud Crowbar 8 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SUSE OpenStack Cloud Crowbar 8 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SUSE OpenStack Cloud 8 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SUSE OpenStack Cloud 8 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SUSE OpenStack Cloud 7 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SUSE OpenStack Cloud 7 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SUSE HPE Helion OpenStack 8 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SUSE HPE Helion OpenStack 8 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
| SUSE Enterprise Storage 5 | python3 | 3.4.10-25.39.3 | SUSE-SU-2020:0497-1 |
| SUSE Enterprise Storage 5 | python3-base | 3.4.10-25.39.2 | SUSE-SU-2020:0497-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | expat | 2.2.0-3.1 | openSUSE-SU-2024:10077-1 |
Advisories 4
- RHSA-2012:0731 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- DSA-2525-1 expat - several Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10077-1 expat-2.2.0-3.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:0497-1 Security update for python3 SUSE / openSUSE Security Updates · Feb 4, 2026
References
- 49504 third-party-advisory
- http://sourceforge.net/tracker/?func=detail&atid=110127&aid=3496608&group_id=10127
- https://www.tenable.com/security/tns-2016-20
- USN-1527-1 vendor-advisory
- http://bugs.python.org/issue13703#msg151870
- https://support.apple.com/HT205637
- 51040 third-party-advisory
- RHSA-2012:0731 vendor-advisory
- 52379 vdb-entry
- http://sourceforge.net/projects/expat/files/expat/2.1.0/
- RHSA-2016:0062 vendor-advisory
- APPLE-SA-2013-10-22-3 vendor-advisory
- APPLE-SA-2015-12-08-3 vendor-advisory
- DSA-2525 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
- MDVSA-2012:041 vendor-advisory
- RHSA-2016:2957 vendor-advisory
- USN-1613-2 vendor-advisory
- [Expat-discuss] 20120304 Announcement: Expat 2.1.0 Beta can be tested mailing-list
- 51024 third-party-advisory
- USN-1613-1 vendor-advisory
- https://kc.mcafee.com/corporate/index?page=content&id=SB10365