Description
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
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 | 2.2.6-2 | — |
| Debian 13 | expat | 2.2.6-2 | — |
| Debian 12 | expat | 2.2.6-2 | — |
| Debian 12 | libxmltok | No fix yet | — |
| Debian 9 | expat | 2.2.0-2+deb9u2 | DSA-4472-1 |
| Debian 8 | expat | 2.1.0-6+deb8u5 | DLA-1839-1 |
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 | expat | 2.2.5-3ubuntu0.1 | USN-4040-1 |
| Ubuntu 18.04 LTS | vnc4 +2 | No fix yet | — |
| Ubuntu 16.04 LTS | cadaver +2 | No fix yet | — |
| Ubuntu 16.04 LTS | expat | 2.1.0-7ubuntu0.16.04.4 | USN-4040-1 |
| Ubuntu Pro 26.04 LTS | swish-e | No fix yet | — |
| Ubuntu Pro 24.04 LTS | libxmltok | 1.2-4.1ubuntu2.24.0.4.1+esm2 | USN-7199-1 |
| Ubuntu Pro 24.04 LTS | swish-e +1 | No fix yet | — |
| Ubuntu Pro 22.04 LTS | libxmltok | 1.2-4ubuntu0.22.04.1~esm4 | USN-7199-1, USN-5455-1 |
| Ubuntu Pro 22.04 LTS | swish-e +1 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | libxmltok | 1.2-4ubuntu0.20.04.1~esm4 | USN-7199-1, USN-5455-1 |
| Ubuntu Pro 20.04 LTS | swish-e +1 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | coin3 +2 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | libxmltok | 1.2-4ubuntu0.18.04.1~esm4 | USN-7199-1, USN-5455-1 |
| Ubuntu Pro 16.04 LTS | libxmltok | 1.2-3ubuntu0.16.04.1~esm2 | USN-5455-1 |
| Ubuntu Pro 16.04 LTS | vnc4 +6 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | vtk | 5.10.1+dfsg-2.1ubuntu0.1~esm1 | USN-4852-1 |
| Ubuntu Pro 14.04 LTS | expat | 2.1.0-4ubuntu1.4+esm1 | USN-4040-2 |
| Ubuntu Pro 14.04 LTS | vnc4 +2 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | vtk | 5.8.0-14.1ubuntu3+esm1 | USN-4852-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | expat +1 | 2.2.5-4.el8 | RHSA-2020:4484 |
| RHEL 8 | mingw-expat +2 | 2.2.4-5.el8 | RHSA-2020:4846 |
| RHEL 7 | expat +2 | 2.1.0-12.el7 | RHSA-2020:3952 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.2 AUS | expat | 2.2.10-1.el8_2 | RHSA-2025:22871 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-curl +2 | 7.64.1-36.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +6 | 2.4.37-57.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_cluster-native | 1.3.14-4.Final_redhat_2.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_http2 | 1.15.7-3.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_jk +2 | 1.2.48-4.redhat_1.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_md | 1:2.0.8-24.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_security | 2.9.2-51.GA.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.37-57.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-nghttp2 +1 | 1.39.2-25.jbcs.el6 | RHSA-2020:2644 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl-pkcs11 | 0.4.10-7.jbcs.el7 | RHSA-2020:2644 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | mingw32-expat +1 | 2.2.4-5.el8 | ALSA-2020:4846 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | expat | 2.2.5-4.el8 | RLSA-2020:4484 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | expat | 2.2.5-3.3.1 | SUSE-SU-2019:1835-1 |
| SLES 15 | expat | 2.2.5-3.3.1 | SUSE-SU-2019:1835-1 |
| SLES 12 SP4 | expat | 2.1.0-21.6.1 | SUSE-SU-2019:1834-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP4 | expat | 2.1.0-21.6.1 | SUSE-SU-2019:1834-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | expat | 2.4.1-1.2 | openSUSE-SU-2024:10748-1 |
| openSUSE Leap 15.1 | expat | 2.2.5-lp151.3.3.1 | openSUSE-SU-2019:1777-1 |
| openSUSE Leap 15.0 | expat | 2.2.5-lp151.3.3.1 | openSUSE-SU-2019:1777-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | expat | 2.2.7-r0 | — |
| Alpine v3.23 | expat | 2.2.7-r0 | — |
| Alpine v3.22 | expat | 2.2.7-r0 | — |
| Alpine v3.21 | expat | 2.2.7-r0 | — |
| Alpine v3.20 | expat | 2.2.7-r0 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | expat | 2.2.7-r0 | — |
| Alpine v3.18 | expat | 2.2.7-r0 | — |
| Alpine v3.17 | expat | 2.2.7-r0 | — |
| Alpine v3.16 | expat | 2.2.7-r0 | — |
| Alpine v3.15 | expat | 2.2.7-r0 | — |
| Alpine v3.14 | expat | 2.2.7-r0 | — |
| Alpine v3.13 | expat | 2.2.7-r0 | — |
| Alpine v3.12 | expat | 2.2.7-r0 | — |
| Alpine v3.11 | expat | 2.2.7-r0 | — |
| Alpine v3.10 | expat | 2.2.7-r0 | — |
| Alpine v3.9 | expat | 2.2.7-r0 | — |
| Alpine v3.8 | expat | 2.2.7-r0 | — |
| Alpine v3.7 | expat | 2.2.7-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | expat +2 | 2.1.0-12.amzn2 | ALAS2-2020-1513 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | expat +1 | 2.2.5-4.el8 | ELSA-2020-4484 |
| Oracle Linux 7 | expat +2 | 2.1.0-12.el7 | ELSA-2020-3952 |
Advisories 25
- ALSA-2020:4846 Moderate: mingw-expat security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2025:22871 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- SSA-398330 SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 Siemens ProductCERT · Oct 13, 2026
- RHSA-2020:4846 Red Hat Security Advisory: mingw-expat security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2020:4484 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2020:3952 Red Hat Security Advisory: expat security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2020:2644 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP3 security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- WID-SEC-2025-0227 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- USN-4852-1 vtk vulnerabilities Ubuntu Security Notices (USN) · Jun 29, 2026
- USN-5455-1 libxmltok vulnerabilities Ubuntu Security Notices (USN) · Jun 25, 2026
- USN-7199-1 libxmltok vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-4040-2 expat vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-4040-1 expat vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-4472-1 expat - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1839-1 expat - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2020:4484 Moderate: expat security update Rocky Linux Security Advisories · Feb 4, 2026
- SUSE-SU-2019:1835-1 Security update for expat SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10748-1 expat-2.4.1-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:1834-1 Security update for expat SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:1777-1 Security update for expat SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2024-1735 expat: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Dec 8, 2025
- ICSA-23-348-10 Siemens SIMATIC S7-1500 CISA ICS & IT advisories · Aug 12, 2025
- ELSA-2020-4484 Moderate: expat security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 10, 2020
- ALAS2-2020-1513 Moderate: expat security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Oct 22, 2020
- ELSA-2020-3952 Moderate: expat security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 6, 2020
References
- USN-4040-1 vendor-advisory
- USN-4040-2 vendor-advisory
- DSA-4472 vendor-advisory
- 20190628 [SECURITY] [DSA 4472-1] expat security update mailing-list
- [debian-lts-announce] 20190629 [SECURITY] [DLA 1839-1] expat security update mailing-list
- FEDORA-2019-18868e1715 vendor-advisory
- FEDORA-2019-139fcda84d vendor-advisory
- openSUSE-SU-2019:1777 vendor-advisory
- GLSA-201911-08 vendor-advisory
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://github.com/libexpat/libexpat/issues/186
- https://github.com/libexpat/libexpat/pull/262
- https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6
- https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/Changes
- https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226
- https://security.netapp.com/advisory/ntap-20190703-0001/
- https://support.f5.com/csp/article/K51011533
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.tenable.com/security/tns-2021-11