# CVE-2018-20843: expat: In libexpat in Expat before 2.2.7, XML input including XML names thatcontain a large number of colons could make the...

CVE-2018-20843 is fixed in 7 products on 1 platform, first by expat 2.2.5-3ubuntu0.1, released June 23, 2019. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2018-20843
- Priority: High
- CVSS: 7.5 (Low)
- EPSS: 0.0711
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 23, 2019

## Description

In libexpat in Expat before 2.2.7, XML input including XML names thatcontain a large number of colons could make the XML parser consume a highamount of RAM and CPU resources while processing (enough to be usable fordenial-of-service attacks).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | expat RHEL 8 | 0:2.2.5-4.el8 | [RHSA-2020:4484](https://patchblox.com/security/data/fix/linux/rhsa-2020-4484.md) | Nov 4, 2020 |
| Linux | expat Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.1 | [expat 2.2.5-3ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-expat-2.2.5-3ubuntu0.1.md) | Jun 23, 2019 |
| Linux | expat Ubuntu 24.10 (oracular) | 2.2.6-2 | [expat 2.2.6-2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-expat-2.2.6-2.md) | Jun 24, 2019 |
| Linux | expat Ubuntu 25.04 (plucky) | 2.2.6-2 | [expat 2.2.6-2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-expat-2.2.6-2.md) | Jun 24, 2019 |
| Linux | expat ol 8 | 0:2.2.5-4.el8 | [ELSA-2020-4484](https://patchblox.com/security/data/fix/linux/elsa-2020-4484.md) | Nov 10, 2020 |
| Linux | expat-devel RHEL 8 | 0:2.2.5-4.el8 | [RHSA-2020:4484](https://patchblox.com/security/data/fix/linux/rhsa-2020-4484.md) | Nov 4, 2020 |
| Linux | expat-devel ol 8 | 0:2.2.5-4.el8 | [ELSA-2020-4484](https://patchblox.com/security/data/fix/linux/elsa-2020-4484.md) | Nov 10, 2020 |
| Linux | libexpat1 Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.1 | [libexpat1 2.2.5-3ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libexpat1-2.2.5-3ubuntu0.1.md) | Jun 23, 2019 |
| Linux | libexpat1 Ubuntu 24.10 (oracular) | 2.2.6-2 | [libexpat1 2.2.6-2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-libexpat1-2.2.6-2.md) | Jun 24, 2019 |
| Linux | libexpat1 Ubuntu 25.04 (plucky) | 2.2.6-2 | [libexpat1 2.2.6-2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libexpat1-2.2.6-2.md) | Jun 24, 2019 |
| Linux | libxmltok1 Ubuntu 18.04.6 LTS (bionic) | 1.2-4ubuntu0.18.04.1~esm4 | [libxmltok1 1.2-4ubuntu0.18.04.1~esm4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxmltok1-1.2-4ubuntu0.18.04.1-esm4.md) | Jan 10, 2022 |
| Linux | libxmltok1 Ubuntu 20.04 LTS (focal) | 1.2-4ubuntu0.20.04.1~esm4 | [libxmltok1 1.2-4ubuntu0.20.04.1~esm4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxmltok1-1.2-4ubuntu0.20.04.1-esm4.md) | Jan 10, 2022 |
| Linux | libxmltok1 Ubuntu 22.04.1 LTS (jammy) | 1.2-4ubuntu0.22.04.1~esm4 | [libxmltok1 1.2-4ubuntu0.22.04.1~esm4](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libxmltok1-1.2-4ubuntu0.22.04.1-esm4.md) | Jan 10, 2022 |
| Linux | libxmltok1t64 Ubuntu 24.04.5 LTS (noble) | 1.2-4.1ubuntu2.24.0.4.1+esm2 | [libxmltok1t64 1.2-4.1ubuntu2.24.0.4.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libxmltok1t64-1.2-4.1ubuntu2.24.0.4.1-esm2.md) | Jan 10, 2022 |
| Linux | libxmltok1t64 Ubuntu 24.10 (oracular) | 1.2-4.1ubuntu3.1 | [libxmltok1t64 1.2-4.1ubuntu3.1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-libxmltok1t64-1.2-4.1ubuntu3.1.md) | Sep 4, 2019 |
| Linux | mingw32-expat RHEL 8 | 0:2.2.4-5.el8 | [RHSA-2020:4846](https://patchblox.com/security/data/fix/linux/rhsa-2020-4846.md) | Nov 4, 2020 |
| Linux | mingw64-expat RHEL 8 | 0:2.2.4-5.el8 | [RHSA-2020:4846](https://patchblox.com/security/data/fix/linux/rhsa-2020-4846.md) | Nov 4, 2020 |

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