# CVE-2020-26952: Firefox ESR and 1 other: Incorrect bookkeeping of functions inlined during JIT compilation could have led to memory corruption…

CVE-2020-26952 is fixed in 4 products on 2 platforms, first by firefox 83.0+build2-0ubuntu0.18.04.2, released November 16, 2020. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2020-26952
- Priority: High
- CVSS: 8.8 (Medium)
- EPSS: 0.0116
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 16, 2020
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2020-26952

## Description

Incorrect bookkeeping of functions inlined during JIT compilation could have led to memory corruption and a potentially exploitable crash when handling out-of-memory errors. This vulnerability affects Firefox < 83.

## 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 |
| Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 83.0+build2-0ubuntu0.18.04.2 | [firefox 83.0+build2-0ubuntu0.18.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-83.0-build2-0ubuntu0.18.04.2.md) | Nov 16, 2020 |
| Linux | firefox Ubuntu 20.04 LTS (focal) | 83.0+build2-0ubuntu0.20.04.1 | [firefox 83.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-83.0-build2-0ubuntu0.20.04.1.md) | Nov 16, 2020 |
| Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 83.0+build2-0ubuntu0.18.04.2 | [firefox-geckodriver 83.0+build2-0ubuntu0.18.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-83.0-build2-0ubuntu0.18.04.2.md) | Nov 16, 2020 |
| Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 83.0+build2-0ubuntu0.20.04.1 | [firefox-geckodriver 83.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-83.0-build2-0ubuntu0.20.04.1.md) | Nov 16, 2020 |
| Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 83.0+build2-0ubuntu0.18.04.2 | [firefox-mozsymbols 83.0+build2-0ubuntu0.18.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-83.0-build2-0ubuntu0.18.04.2.md) | Nov 16, 2020 |
| Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 83.0+build2-0ubuntu0.20.04.1 | [firefox-mozsymbols 83.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-83.0-build2-0ubuntu0.20.04.1.md) | Nov 16, 2020 |

---

Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.