CVE catalog
CVE-2018-20843
xmltok library vulnerabilities
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 7.11% · Oct 22, 2026
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).
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 | fixed |
| Debian | expat | trixie-security | 2.9.0-1~deb13u1 | fixed |
| Debian | expat | bookworm | 2.5.0-1+deb12u2 | fixed |
| Debian | expat | bookworm-security | 2.5.0-1+deb12u5 | fixed |
| Debian | libxmltok | bookworm | 1.2-4 | vulnerable |
| Ubuntu | libxmltok | noble | Not reported | vulnerable |
| Ubuntu | expat | noble | 2.2.6-2 | fixed |
| Ubuntu | libxmltok | noble | 1.2-4.1ubuntu2.24.0.4.1+esm2 | fixed |
| Ubuntu | libxmltok1-dev | noble | 1.2-4.1ubuntu2.24.0.4.1+esm2 | fixed |
| Ubuntu | libxmltok1t64 | noble | 1.2-4.1ubuntu2.24.0.4.1+esm2 | fixed |
| Cpe | libexpat | Not reported | 2.2.7 | fixed |
| Cpe | ubuntu_linux | Not reported | Not reported | unknown |
| Cpe | debian_linux | Not reported | Not reported | unknown |
| Cpe | fedora | Not reported | Not reported | unknown |
| Cpe | leap | Not reported | Not reported | unknown |
| Cpe | hospitality_res_3700 | Not reported | Not reported | unknown |
| Cpe | http_server | Not reported | Not reported | unknown |
| Cpe | outside_in_technology | Not reported | Not reported | unknown |
| Cpe | nessus | Not reported | 8.15.0 | fixed |
| Ubuntu | vtk | pro | 5.10.1+dfsg-2 | vulnerable |
| Ubuntu | vtk | pro | 5.10.1+dfsg-2build3 | vulnerable |
| Ubuntu | vtk | pro | 5.10.1+dfsg-2.1build1 | vulnerable |
| Ubuntu | vtk | pro | 5.10.1+dfsg-2.1ubuntu0.1~esm1 | fixed |
| Alpine | expat | 3.10 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.11 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.12 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.13 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.14 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.15 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.16 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.17 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.18 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.19 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.20 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.21 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.22 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.23 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.24 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.7 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.8 | 2.2.7-r0 | fixed |
| Alpine | expat | 3.9 | 2.2.7-r0 | fixed |
| Ubuntu | expat | pro | 2.1.0-4 | vulnerable |
| Ubuntu | expat | pro | 2.1.0-4ubuntu1 | vulnerable |
| Ubuntu | expat | pro | 2.1.0-4ubuntu1.1 | vulnerable |
| Ubuntu | expat | pro | 2.1.0-4ubuntu1.2 | vulnerable |
| Ubuntu | expat | pro | 2.1.0-4ubuntu1.3 | vulnerable |
| Ubuntu | expat | pro | 2.1.0-4ubuntu1.4 | vulnerable |
| Ubuntu | expat | pro | 2.1.0-4ubuntu1.4+esm1 | fixed |
| Ubuntu | expat | 16.04 | 2.1.0-7 | vulnerable |
| Ubuntu | expat | 16.04 | 2.1.0-7ubuntu0.16.04.1 | vulnerable |
| Ubuntu | expat | 16.04 | 2.1.0-7ubuntu0.16.04.2 | vulnerable |
| Ubuntu | expat | 16.04 | 2.1.0-7ubuntu0.16.04.3 | vulnerable |
| Ubuntu | expat | 16.04 | 2.1.0-7ubuntu0.16.04.4 | fixed |
| Ubuntu | expat | 18.04 | 2.2.3-1 | vulnerable |
| Ubuntu | expat | 18.04 | 2.2.3-2 | vulnerable |
| Ubuntu | expat | 18.04 | 2.2.5-0ubuntu2 | vulnerable |
| Ubuntu | expat | 18.04 | 2.2.5-3 | vulnerable |
| Ubuntu | expat | 18.04 | 2.2.5-3ubuntu0.1 | fixed |
| Suse | expat | linux enterprise module for basesystem 15 | 2.2.5-3.3.1 | fixed |
| Suse | expat | linux enterprise module for basesystem 15 sp1 | 2.2.5-3.3.1 | fixed |
| Suse | expat | linux enterprise desktop 12 sp4 | 2.1.0-21.6.1 | fixed |
| Suse | expat | linux enterprise software development kit 12 sp4 | 2.1.0-21.6.1 | fixed |
| Suse | expat | linux enterprise server 12 sp4 | 2.1.0-21.6.1 | fixed |
| Suse | expat | linux enterprise server for sap applications 12 sp4 | 2.1.0-21.6.1 | fixed |
| Opensuse | expat | leap 15.0 | 2.2.5-lp151.3.3.1 | fixed |
| Opensuse | expat | leap 15.1 | 2.2.5-lp151.3.3.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | expat | source | sid | 2.2.6-2 | not yet assigned | Not reported | [931031] |
| Debian | expat | source | forky | 2.2.6-2 | not yet assigned | Not reported | [931031] |
| Debian | expat | source | trixie | 2.2.6-2 | not yet assigned | Not reported | [931031] |
| Debian | expat | source | bookworm | 2.2.6-2 | not yet assigned | Not reported | [931031] |
| Debian | libxmltok | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Ubuntu | expat | deb | noble | 2.2.6-2 | Not reported | Not reported | Not reported |
| Ubuntu | libxmltok | deb | noble | 1.2-4.1ubuntu2.24.0.4.1+esm2 | Not reported | Not reported | Not reported |
| Ubuntu | libxmltok1-dev | deb | noble | 1.2-4.1ubuntu2.24.0.4.1+esm2 | Not reported | Not reported | Not reported |
| Ubuntu | libxmltok1t64 | deb | noble | 1.2-4.1ubuntu2.24.0.4.1+esm2 | Not reported | Not reported | Not reported |
| Cpe | libexpat | cpe | Not reported | 2.2.7 | Not reported | NVD-CVE-2018-20843 | Not reported |
| Cpe | nessus | cpe | Not reported | 8.15.0 | Not reported | NVD-CVE-2018-20843 | Not reported |
| Ubuntu | vtk | deb | pro | 5.10.1+dfsg-2.1ubuntu0.1~esm1 | Not reported | USN-4852-1 | Not reported |
| Alpine | expat | apk | 3.10 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.11 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.12 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.13 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.14 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.15 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.16 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.17 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.18 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.19 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.20 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.21 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.22 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.23 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.24 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.7 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.8 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Alpine | expat | apk | 3.9 | 2.2.7-r0 | Not reported | ALPINE-CVE-2018-20843 | Not reported |
| Ubuntu | expat | deb | pro | 2.1.0-4ubuntu1.4+esm1 | Not reported | USN-4040-2 | Not reported |
| Ubuntu | expat | deb | 16.04 | 2.1.0-7ubuntu0.16.04.4 | Not reported | USN-4040-1 | Not reported |
| Ubuntu | expat | deb | 18.04 | 2.2.5-3ubuntu0.1 | Not reported | USN-4040-1 | Not reported |
| Suse | expat | rpm | linux enterprise module for basesystem 15 | 2.2.5-3.3.1 | Not reported | SUSE-SU-2019:1835-1 | Not reported |
| Suse | expat | rpm | linux enterprise module for basesystem 15 sp1 | 2.2.5-3.3.1 | Not reported | SUSE-SU-2019:1835-1 | Not reported |
| Suse | expat | rpm | linux enterprise desktop 12 sp4 | 2.1.0-21.6.1 | Not reported | SUSE-SU-2019:1834-1 | Not reported |
| Suse | expat | rpm | linux enterprise software development kit 12 sp4 | 2.1.0-21.6.1 | Not reported | SUSE-SU-2019:1834-1 | Not reported |
| Suse | expat | rpm | linux enterprise server 12 sp4 | 2.1.0-21.6.1 | Not reported | SUSE-SU-2019:1834-1 | Not reported |
| Suse | expat | rpm | linux enterprise server for sap applications 12 sp4 | 2.1.0-21.6.1 | Not reported | SUSE-SU-2019:1834-1 | Not reported |
| Opensuse | expat | rpm | leap 15.0 | 2.2.5-lp151.3.3.1 | Not reported | OPENSUSE-SU-2019:1777-1 | Not reported |
| Opensuse | expat | rpm | leap 15.1 | 2.2.5-lp151.3.3.1 | Not reported | OPENSUSE-SU-2019:1777-1 | Not reported |
Notes
[bookworm] libxmltok: Minor issue, no runtime dependencies left
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 · bookwormFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u2· arm64 · bookwormFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u3· amd64 · bookworm-securityFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u3· arm64 · bookworm-securityFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
- [libexpat1]Unknown
Source package: [expat]
Details (4)
2.5.0-1+deb12u2· amd64 · bookwormFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u2· arm64 · bookwormFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u3· amd64 · bookworm-securityFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u3· arm64 · bookworm-securityFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
- [libexpat1-dev]Unknown
Source package: [expat]
Details (4)
2.5.0-1+deb12u2· amd64 · bookwormFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u2· arm64 · bookwormFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u3· amd64 · bookworm-securityFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
2.5.0-1+deb12u3· arm64 · bookworm-securityFixed · Fixed:
2.2.6-2usn · expat · debian · bookworm
- [libxmltok1]Unknown
Source package: [libxmltok]
Details (2)
1.2-4· amd64 · bookwormAffected
usn · libxmltok · debian · bookworm
1.2-4· arm64 · bookwormAffected
usn · libxmltok · debian · bookworm
- [libxmltok1-dev]Unknown
Source package: [libxmltok]
Details (2)
1.2-4· amd64 · bookwormAffected
usn · libxmltok · debian · bookworm
1.2-4· arm64 · bookwormAffected
usn · libxmltok · debian · bookworm
Observed:
References
- [https://access.redhat.com/errata/RHSA-2020:2644]
- [https://cert-portal.siemens.com/productcert/csaf/ssa-398330.json]
- [https://ftp.suse.com/pub/projects/security/]
- [https://nvd.nist.gov/vuln/detail/CVE-2018-20843]
- [https://osv.dev/vulnerability/ALPINE-CVE-2018-20843]
- [https://osv.dev/vulnerability/DLA-1839-1]
- [https://osv.dev/vulnerability/DSA-4472-1]
- [https://osv.dev/vulnerability/SUSE-SU-2019:1834-1]
- [https://osv.dev/vulnerability/SUSE-SU-2019:1835-1]
- [https://osv.dev/vulnerability/USN-4040-1]
- [https://osv.dev/vulnerability/USN-4040-2]
- [https://osv.dev/vulnerability/USN-4852-1]
- [https://osv.dev/vulnerability/openSUSE-SU-2019:1777-1]
- [https://security-tracker.debian.org/tracker/CVE-2018-20843]
- [https://ubuntu.com/security/notices/USN-7199-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2021/wid-sec-w-2025-0227.json]
[CERT-Bund public advisories] · [CISA cybersecurity 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)]