What’s Vulnerable › Vulnerabilities

CVE-2023-6867

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-12-19 · updated 2026-06-17
• Weakness: CWE-1021

Description

The timing of a button click causing a popup to disappear was approximately the same length as the anti-clickjacking delay on permission prompts. It was possible to use this fact to surprise users by luring them to click where the permission grant button would be about to appear. This vulnerability affects Firefox ESR < 115.6 and Firefox < 121.

Affected products

• Debian Linux: 10.0, 11.0, 12.0
• Mozilla Firefox: before 121.0 — fixed in 121.0
• Mozilla Firefox ESR: before 115.6 — fixed in 115.6

How to fix

Upgrade to a fixed version: Mozilla Firefox 121.0; Mozilla Firefox ESR 115.6. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1863863
• https://lists.debian.org/debian-lts-announce/2023/12/msg00020.html
• https://security.gentoo.org/glsa/202401-10
• https://www.debian.org/security/2023/dsa-5581
• https://www.mozilla.org/security/advisories/mfsa2023-54/
• https://www.mozilla.org/security/advisories/mfsa2023-56/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1863863
• https://lists.debian.org/debian-lts-announce/2023/12/msg00020.html
• https://security.gentoo.org/glsa/202401-10
• https://www.debian.org/security/2023/dsa-5581
• https://www.mozilla.org/security/advisories/mfsa2023-54/
• https://www.mozilla.org/security/advisories/mfsa2023-56/

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