# CVE-2019-11759: Firefox ESR: An attacker could have caused 4 bytes of HMAC output to be written past the end of a buffer stored on…

CVE-2019-11759 is fixed in 10 products on 2 platforms, first by thunderbird 1:68.2.1+build1-0ubuntu0.18.04.1, released October 22, 2019. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2019-11759
- Priority: Urgent
- CVSS: 8.8 (Critical)
- EPSS: 0.0165
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 22, 2019
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2019-11759

## Description

An attacker could have caused 4 bytes of HMAC output to be written past the end of a buffer stored on the stack. This could be used by an attacker to execute arbitrary code or more likely lead to a crash. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Mozilla Firefox ESR (en-US) | 78.0esr | [Mozilla Firefox ESR (en-US) 78.0esr](https://patchblox.com/security/data/fix/windows-app/mozilla.firefox.esr-78.0esr.md) | Jun 25, 2020 |
| Linux | firefox RHEL 8 | 0:68.2.0-2.el8_0 | [RHSA-2019:3196](https://patchblox.com/security/data/fix/linux/rhsa-2019-3196.md) | Oct 24, 2019 |
| Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 70.0+build2-0ubuntu0.18.04.1 | [firefox 70.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-70.0-build2-0ubuntu0.18.04.1.md) | Jul 9, 2020 |
| Linux | firefox Ubuntu 20.04 LTS (focal) | 70.0+build2-0ubuntu1 | [firefox 70.0+build2-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-70.0-build2-0ubuntu1.md) | Jul 9, 2020 |
| Linux | firefox ol 8 | 0:68.2.0-2.0.1.el8_0 | [ELSA-2019-3196](https://patchblox.com/security/data/fix/linux/elsa-2019-3196.md) | Oct 24, 2019 |
| Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 70.0+build2-0ubuntu0.18.04.1 | [firefox-geckodriver 70.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-70.0-build2-0ubuntu0.18.04.1.md) | Jul 9, 2020 |
| Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 70.0+build2-0ubuntu1 | [firefox-geckodriver 70.0+build2-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-70.0-build2-0ubuntu1.md) | Jul 9, 2020 |
| Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 70.0+build2-0ubuntu0.18.04.1 | [firefox-mozsymbols 70.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-70.0-build2-0ubuntu0.18.04.1.md) | Jul 9, 2020 |
| Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 70.0+build2-0ubuntu1 | [firefox-mozsymbols 70.0+build2-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-70.0-build2-0ubuntu1.md) | Jul 9, 2020 |
| Linux | thunderbird RHEL 8 | 0:68.2.0-1.el8_0 | [RHSA-2019:3237](https://patchblox.com/security/data/fix/linux/rhsa-2019-3237.md) | Oct 29, 2019 |
| Linux | thunderbird Ubuntu 18.04.6 LTS (bionic) | 1:68.2.1+build1-0ubuntu0.18.04.1 | [thunderbird 1:68.2.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-1-68.2.1-build1-0ubuntu0.18.04.1.md) | Oct 22, 2019 |
| Linux | thunderbird ol 8 | 0:68.2.0-1.0.1.el8_0 | [ELSA-2019-3237](https://patchblox.com/security/data/fix/linux/elsa-2019-3237.md) | Oct 30, 2019 |
| Linux | thunderbird-gnome-support Ubuntu 18.04.6 LTS (bionic) | 1:68.2.1+build1-0ubuntu0.18.04.1 | [thunderbird-gnome-support 1:68.2.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-gnome-support-1-68.2.1-build1-0ubuntu0.18.04.1.md) | Oct 22, 2019 |
| Linux | thunderbird-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 1:68.2.1+build1-0ubuntu0.18.04.1 | [thunderbird-mozsymbols 1:68.2.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-mozsymbols-1-68.2.1-build1-0ubuntu0.18.04.1.md) | Oct 22, 2019 |
| Linux | xul-ext-calendar-timezones Ubuntu 18.04.6 LTS (bionic) | 1:68.2.1+build1-0ubuntu0.18.04.1 | [xul-ext-calendar-timezones 1:68.2.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-calendar-timezones-1-68.2.1-build1-0ubuntu0.18.04.1.md) | Oct 22, 2019 |
| Linux | xul-ext-gdata-provider Ubuntu 18.04.6 LTS (bionic) | 1:68.2.1+build1-0ubuntu0.18.04.1 | [xul-ext-gdata-provider 1:68.2.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-gdata-provider-1-68.2.1-build1-0ubuntu0.18.04.1.md) | Oct 22, 2019 |
| Linux | xul-ext-lightning Ubuntu 18.04.6 LTS (bionic) | 1:68.2.1+build1-0ubuntu0.18.04.1 | [xul-ext-lightning 1:68.2.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-lightning-1-68.2.1-build1-0ubuntu0.18.04.1.md) | Oct 22, 2019 |

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