# CVE-2021-29989: Firefox ESR and 3 others: Mozilla developers reported memory safety bugs present in Firefox 90 and Firefox ESR 78.12.

CVE-2021-29989 is fixed in 11 products on 2 platforms, first by Mozilla Firefox ESR (en-US) 91.0, released August 4, 2021. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-29989
- Priority: High
- CVSS: 8.8 (Important)
- EPSS: 0.0127
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 10, 2021
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2021-29989

## Description

Mozilla developers reported memory safety bugs present in Firefox 90 and Firefox ESR 78.12. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 78.13, Firefox ESR < 78.13, and Firefox < 91.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Mozilla Firefox ESR (en-US) | 91.0 | [Mozilla Firefox ESR (en-US) 91.0](https://patchblox.com/security/data/fix/windows-app/mozilla.firefox.esr-91.0.md) | Aug 4, 2021 |
| Windows apps | Mozilla Thunderbird (en-US) | 91.0.3 | [Mozilla Thunderbird (en-US) 91.0.3](https://patchblox.com/security/data/fix/windows-app/mozilla.thunderbird-91.0.3.md) | Aug 24, 2021 |
| Linux | firefox RHEL 8 | 0:78.13.0-2.el8_4 | [RHSA-2021:3157](https://patchblox.com/security/data/fix/linux/rhsa-2021-3157.md) | Aug 16, 2021 |
| Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 91.0+build2-0ubuntu0.18.04.1 | [firefox 91.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-91.0-build2-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | firefox Ubuntu 20.04 LTS (focal) | 91.0+build2-0ubuntu0.20.04.1 | [firefox 91.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-91.0-build2-0ubuntu0.20.04.1.md) | Aug 10, 2021 |
| Linux | firefox ol 8 | 0:78.13.0-2.0.1.el8_4 | [ELSA-2021-3157](https://patchblox.com/security/data/fix/linux/elsa-2021-3157.md) | Aug 17, 2021 |
| Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 91.0+build2-0ubuntu0.18.04.1 | [firefox-geckodriver 91.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-91.0-build2-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 91.0+build2-0ubuntu0.20.04.1 | [firefox-geckodriver 91.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-91.0-build2-0ubuntu0.20.04.1.md) | Aug 10, 2021 |
| Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 91.0+build2-0ubuntu0.18.04.1 | [firefox-mozsymbols 91.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-91.0-build2-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 91.0+build2-0ubuntu0.20.04.1 | [firefox-mozsymbols 91.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-91.0-build2-0ubuntu0.20.04.1.md) | Aug 10, 2021 |
| Linux | thunderbird RHEL 8 | 0:78.13.0-1.el8_4 | [RHSA-2021:3155](https://patchblox.com/security/data/fix/linux/rhsa-2021-3155.md) | Aug 16, 2021 |
| Linux | thunderbird Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [thunderbird 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | thunderbird Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [thunderbird 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | thunderbird ol 8 | 0:78.13.0-1.0.1.el8_4 | [ELSA-2021-3155](https://patchblox.com/security/data/fix/linux/elsa-2021-3155.md) | Aug 17, 2021 |
| Linux | thunderbird-gnome-support Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [thunderbird-gnome-support 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-gnome-support-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | thunderbird-gnome-support Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [thunderbird-gnome-support 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-gnome-support-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | thunderbird-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [thunderbird-mozsymbols 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-mozsymbols-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | thunderbird-mozsymbols Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [thunderbird-mozsymbols 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-thunderbird-mozsymbols-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | xul-ext-calendar-timezones Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [xul-ext-calendar-timezones 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-calendar-timezones-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | xul-ext-calendar-timezones Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [xul-ext-calendar-timezones 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-calendar-timezones-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | xul-ext-gdata-provider Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [xul-ext-gdata-provider 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-gdata-provider-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | xul-ext-gdata-provider Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [xul-ext-gdata-provider 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-gdata-provider-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |
| Linux | xul-ext-lightning Ubuntu 18.04.6 LTS (bionic) | 1:78.13.0+build1-0ubuntu0.18.04.1 | [xul-ext-lightning 1:78.13.0+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-lightning-1-78.13.0-build1-0ubuntu0.18.04.1.md) | Aug 10, 2021 |
| Linux | xul-ext-lightning Ubuntu 20.04 LTS (focal) | 1:78.13.0+build1-0ubuntu0.20.04.2 | [xul-ext-lightning 1:78.13.0+build1-0ubuntu0.20.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xul-ext-lightning-1-78.13.0-build1-0ubuntu0.20.04.2.md) | Aug 10, 2021 |

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