# CVE-2017-7805: firefox: During TLS 1.2 exchanges, handshake hashes are generated which point to a message buffer

CVE-2017-7805 is fixed in 14 products on 1 platform, first by libnss3 2:3.32-1ubuntu3, released September 28, 2017. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2017-7805
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0305
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 28, 2017

## Description

During TLS 1.2 exchanges, handshake hashes are generated which point to a message buffer. This saved data is used for later messages but in some cases, the handshake transcript can exceed the space available in the current buffer, causing the allocation of a new buffer. This leaves a pointer pointing to the old, freed buffer, resulting in a use-after-free when handshake hashes are then calculated afterwards. This can result in a potentially exploitable crash. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 56.0+build6-0ubuntu1 | [firefox 56.0+build6-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-56.0-build6-0ubuntu1.md) | Oct 1, 2017 |
| Linux | firefox-globalmenu Ubuntu 18.04.6 LTS (bionic) | 56.0+build6-0ubuntu1 | [firefox-globalmenu 56.0+build6-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-globalmenu-56.0-build6-0ubuntu1.md) | Oct 1, 2017 |
| Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 56.0+build6-0ubuntu1 | [firefox-mozsymbols 56.0+build6-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-56.0-build6-0ubuntu1.md) | Oct 1, 2017 |
| Linux | firefox-testsuite Ubuntu 18.04.6 LTS (bionic) | 56.0+build6-0ubuntu1 | [firefox-testsuite 56.0+build6-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-testsuite-56.0-build6-0ubuntu1.md) | Oct 1, 2017 |
| Linux | libnss3 Ubuntu 18.04.6 LTS (bionic) | 2:3.32-1ubuntu3 | [libnss3 2:3.32-1ubuntu3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libnss3-2-3.32-1ubuntu3.md) | Sep 28, 2017 |
| Linux | libnss3-tools Ubuntu 18.04.6 LTS (bionic) | 2:3.32-1ubuntu3 | [libnss3-tools 2:3.32-1ubuntu3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libnss3-tools-2-3.32-1ubuntu3.md) | Sep 28, 2017 |
| Linux | thunderbird Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [thunderbird 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |
| Linux | thunderbird-globalmenu Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [thunderbird-globalmenu 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-globalmenu-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |
| Linux | thunderbird-gnome-support Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [thunderbird-gnome-support 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-gnome-support-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |
| Linux | thunderbird-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [thunderbird-mozsymbols 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-mozsymbols-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |
| Linux | thunderbird-testsuite Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [thunderbird-testsuite 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-testsuite-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |
| Linux | xul-ext-calendar-timezones Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [xul-ext-calendar-timezones 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-calendar-timezones-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |
| Linux | xul-ext-gdata-provider Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [xul-ext-gdata-provider 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-gdata-provider-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |
| Linux | xul-ext-lightning Ubuntu 18.04.6 LTS (bionic) | 1:52.4.0+build1-0ubuntu2 | [xul-ext-lightning 1:52.4.0+build1-0ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-lightning-1-52.4.0-build1-0ubuntu2.md) | Oct 1, 2017 |

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