CVE-2025-6429 Affecting firefox-esr package, versions <128.12.0esr-1~deb12u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.03% (8th percentile)

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  • Snyk IDSNYK-DEBIAN12-FIREFOXESR-10498738
  • published25 Jun 2025
  • disclosed24 Jun 2025

Introduced: 24 Jun 2025

NewCVE-2025-6429  (opens in a new tab)

How to fix?

Upgrade Debian:12 firefox-esr to version 128.12.0esr-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream firefox-esr package and not the firefox-esr package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an embed tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerability affects Firefox < 140 and Firefox ESR < 128.12.

CVSS Base Scores

version 3.1