# CVE-2020-15678: Firefox ESR and 2 others: When recursing through graphical layers while scrolling, an iterator may have become invalid, resulting…

CVE-2020-15678 is fixed in 11 products on 2 platforms, first by RHSA-2020:3832, released September 24, 2020. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2020-15678
- Priority: High
- CVSS: 8.8 (Important)
- EPSS: 0.0188
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 24, 2020
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2020-15678

## Description

When recursing through graphical layers while scrolling, an iterator may have become invalid, resulting in a potential use-after-free. This occurs because the function APZCTreeManager::ComputeClippedCompositionBounds did not follow iterator invalidation rules. This vulnerability affects Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.

## 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) | 78.4.0 | [Mozilla Thunderbird (en-US) 78.4.0](https://patchblox.com/security/data/fix/windows-app/mozilla.thunderbird-78.4.0.md) | Oct 19, 2020 |
| Linux | firefox RHEL 8 | 0:78.3.0-1.el8_2 | [RHSA-2020:3832](https://patchblox.com/security/data/fix/linux/rhsa-2020-3832.md) | Sep 24, 2020 |
| Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 81.0+build2-0ubuntu0.18.04.1 | [firefox 81.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-81.0-build2-0ubuntu0.18.04.1.md) | Sep 24, 2020 |
| Linux | firefox Ubuntu 20.04 LTS (focal) | 81.0+build2-0ubuntu0.20.04.1 | [firefox 81.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-81.0-build2-0ubuntu0.20.04.1.md) | Sep 24, 2020 |
| Linux | firefox ol 8 | 0:78.3.0-1.0.1.el8_2 | [ELSA-2020-3832](https://patchblox.com/security/data/fix/linux/elsa-2020-3832.md) | Sep 24, 2020 |
| Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 81.0+build2-0ubuntu0.18.04.1 | [firefox-geckodriver 81.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-81.0-build2-0ubuntu0.18.04.1.md) | Sep 24, 2020 |
| Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 81.0+build2-0ubuntu0.20.04.1 | [firefox-geckodriver 81.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-81.0-build2-0ubuntu0.20.04.1.md) | Sep 24, 2020 |
| Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 81.0+build2-0ubuntu0.18.04.1 | [firefox-mozsymbols 81.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-81.0-build2-0ubuntu0.18.04.1.md) | Sep 24, 2020 |
| Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 81.0+build2-0ubuntu0.20.04.1 | [firefox-mozsymbols 81.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-81.0-build2-0ubuntu0.20.04.1.md) | Sep 24, 2020 |
| Linux | thunderbird RHEL 8 | 0:78.3.1-1.el8_2 | [RHSA-2020:4155](https://patchblox.com/security/data/fix/linux/rhsa-2020-4155.md) | Oct 1, 2020 |
| Linux | thunderbird Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | [thunderbird 1:78.8.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-1-78.8.1-build1-0ubuntu0.18.04.1.md) | Apr 22, 2021 |
| Linux | thunderbird ol 8 | 0:78.3.1-1.0.1.el8_2 | [ELSA-2020-4155](https://patchblox.com/security/data/fix/linux/elsa-2020-4155.md) | Oct 4, 2020 |
| Linux | thunderbird-gnome-support Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | [thunderbird-gnome-support 1:78.8.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-gnome-support-1-78.8.1-build1-0ubuntu0.18.04.1.md) | Apr 22, 2021 |
| Linux | thunderbird-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | [thunderbird-mozsymbols 1:78.8.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-thunderbird-mozsymbols-1-78.8.1-build1-0ubuntu0.18.04.1.md) | Apr 22, 2021 |
| Linux | xul-ext-calendar-timezones Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | [xul-ext-calendar-timezones 1:78.8.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-calendar-timezones-1-78.8.1-build1-0ubuntu0.18.04.1.md) | Apr 22, 2021 |
| Linux | xul-ext-gdata-provider Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | [xul-ext-gdata-provider 1:78.8.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-gdata-provider-1-78.8.1-build1-0ubuntu0.18.04.1.md) | Apr 22, 2021 |
| Linux | xul-ext-lightning Ubuntu 18.04.6 LTS (bionic) | 1:78.8.1+build1-0ubuntu0.18.04.1 | [xul-ext-lightning 1:78.8.1+build1-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-xul-ext-lightning-1-78.8.1-build1-0ubuntu0.18.04.1.md) | Apr 22, 2021 |

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