# CVE-2020-15665: Firefox ESR and 1 other: Firefox did not reset the address bar after the beforeunload dialog was shown if the user chose to remain…

CVE-2020-15665 is fixed in 4 products on 2 platforms, first by firefox 80.0+build2-0ubuntu0.18.04.1, released August 25, 2020. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2020-15665
- Priority: Routine
- CVSS: 4.3 (Medium)
- EPSS: 0.0069
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 25, 2020
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2020-15665

## Description

Firefox did not reset the address bar after the beforeunload dialog was shown if the user chose to remain on the page. This could have resulted in an incorrect URL being shown when used in conjunction with other unexpected browser behaviors. This vulnerability affects Firefox < 80.

## 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) | 80.0+build2-0ubuntu0.18.04.1 | [firefox 80.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-80.0-build2-0ubuntu0.18.04.1.md) | Aug 25, 2020 |
| Linux | firefox Ubuntu 20.04 LTS (focal) | 80.0+build2-0ubuntu0.20.04.1 | [firefox 80.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-80.0-build2-0ubuntu0.20.04.1.md) | Aug 25, 2020 |
| Linux | firefox-geckodriver Ubuntu 18.04.6 LTS (bionic) | 80.0+build2-0ubuntu0.18.04.1 | [firefox-geckodriver 80.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-geckodriver-80.0-build2-0ubuntu0.18.04.1.md) | Aug 25, 2020 |
| Linux | firefox-geckodriver Ubuntu 20.04 LTS (focal) | 80.0+build2-0ubuntu0.20.04.1 | [firefox-geckodriver 80.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-geckodriver-80.0-build2-0ubuntu0.20.04.1.md) | Aug 25, 2020 |
| Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 80.0+build2-0ubuntu0.18.04.1 | [firefox-mozsymbols 80.0+build2-0ubuntu0.18.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-80.0-build2-0ubuntu0.18.04.1.md) | Aug 25, 2020 |
| Linux | firefox-mozsymbols Ubuntu 20.04 LTS (focal) | 80.0+build2-0ubuntu0.20.04.1 | [firefox-mozsymbols 80.0+build2-0ubuntu0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-firefox-mozsymbols-80.0-build2-0ubuntu0.20.04.1.md) | Aug 25, 2020 |

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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

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