# CVE-2021-3518: libxml2: The libxml2 library is a development toolbox providing the implementation of various XML standards.  Security Fix(es)...

CVE-2021-3518 is fixed in 5 products on 1 platform, first by libxml2 2.9.4+dfsg1-6.1ubuntu1.4, released June 1, 2021. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-3518
- Priority: High
- CVSS: 8.8 (Moderate)
- EPSS: 0.2186
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 18, 2021

## Description

The libxml2 library is a development toolbox providing the implementation of various XML standards.  Security Fix(es):  * libxml2: Use-after-free in xmlEncodeEntitiesInternal() in entities.c (CVE-2021-3516)  * libxml2: Heap-based buffer overflow in xmlEncodeEntitiesInternal() in entities.c (CVE-2021-3517)  * libxml2: Use-after-free in xmlXIncludeDoProcess() in xinclude.c (CVE-2021-3518)  * libxml2: NULL pointer dereference when post-validating mixed content parsed in recovery mode (CVE-2021-3537)  * libxml2: Exponential entity expansion attack bypasses all existing protection mechanisms (CVE-2021-3541)  For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libxml2 RHEL 8 | 0:2.9.7-9.el8_4.2 | [RHSA-2021:2569](https://patchblox.com/security/data/fix/linux/rhsa-2021-2569.md) | Jun 29, 2021 |
| Linux | libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.4 | [libxml2 2.9.4+dfsg1-6.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxml2-2.9.4-dfsg1-6.1ubuntu1.4.md) | Jun 1, 2021 |
| Linux | libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.1 | [libxml2 2.9.10+dfsg-5ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxml2-2.9.10-dfsg-5ubuntu0.20.04.1.md) | Jun 1, 2021 |
| Linux | libxml2 ol 8 | 0:2.9.7-9.0.1.el8_4.2 | [ELSA-2021-2569](https://patchblox.com/security/data/fix/linux/elsa-2021-2569.md) | Jul 3, 2021 |
| Linux | libxml2-devel RHEL 8 | 0:2.9.7-9.el8_4.2 | [RHSA-2021:2569](https://patchblox.com/security/data/fix/linux/rhsa-2021-2569.md) | Jun 29, 2021 |
| Linux | libxml2-devel ol 8 | 0:2.9.7-9.0.1.el8_4.2 | [ELSA-2021-2569](https://patchblox.com/security/data/fix/linux/elsa-2021-2569.md) | Jul 3, 2021 |
| Linux | libxml2-utils Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.4 | [libxml2-utils 2.9.4+dfsg1-6.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libxml2-utils-2.9.4-dfsg1-6.1ubuntu1.4.md) | Jun 1, 2021 |
| Linux | libxml2-utils Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.1 | [libxml2-utils 2.9.10+dfsg-5ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxml2-utils-2.9.10-dfsg-5ubuntu0.20.04.1.md) | Jun 1, 2021 |
| Linux | python-libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.4 | [python-libxml2 2.9.4+dfsg1-6.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-libxml2-2.9.4-dfsg1-6.1ubuntu1.4.md) | Jun 1, 2021 |
| Linux | python-libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.1 | [python-libxml2 2.9.10+dfsg-5ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python-libxml2-2.9.10-dfsg-5ubuntu0.20.04.1.md) | Jun 1, 2021 |
| Linux | python3-libxml2 RHEL 8 | 0:2.9.7-9.el8_4.2 | [RHSA-2021:2569](https://patchblox.com/security/data/fix/linux/rhsa-2021-2569.md) | Jun 29, 2021 |
| Linux | python3-libxml2 Ubuntu 18.04.6 LTS (bionic) | 2.9.4+dfsg1-6.1ubuntu1.4 | [python3-libxml2 2.9.4+dfsg1-6.1ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-libxml2-2.9.4-dfsg1-6.1ubuntu1.4.md) | Jun 1, 2021 |
| Linux | python3-libxml2 Ubuntu 20.04 LTS (focal) | 2.9.10+dfsg-5ubuntu0.20.04.1 | [python3-libxml2 2.9.10+dfsg-5ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-python3-libxml2-2.9.10-dfsg-5ubuntu0.20.04.1.md) | Jun 1, 2021 |
| Linux | python3-libxml2 ol 8 | 0:2.9.7-9.0.1.el8_4.2 | [ELSA-2021-2569](https://patchblox.com/security/data/fix/linux/elsa-2021-2569.md) | Jul 3, 2021 |

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