What’s Vulnerable › Vulnerabilities

CVE-2023-6206

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-11-21 · updated 2026-06-17
• Weakness: CWE-1021

Description

The black fade animation when exiting fullscreen is roughly the length of 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 < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

Affected products

• Debian Linux: 10.0, 11.0, 12.0
• Mozilla Firefox: before 120.0 — fixed in 120.0
• Mozilla Firefox ESR: before 115.5.0 — fixed in 115.5.0
• Mozilla Thunderbird: before 115.5 — fixed in 115.5

How to fix

Upgrade to a fixed version: Mozilla Firefox 120.0; Mozilla Firefox ESR 115.5.0; Mozilla Thunderbird 115.5. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1857430
• https://lists.debian.org/debian-lts-announce/2023/11/msg00017.html
• https://lists.debian.org/debian-lts-announce/2023/11/msg00030.html
• https://www.debian.org/security/2023/dsa-5561
• https://www.mozilla.org/security/advisories/mfsa2023-49/
• https://www.mozilla.org/security/advisories/mfsa2023-50/
• https://www.mozilla.org/security/advisories/mfsa2023-52/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1857430
• https://lists.debian.org/debian-lts-announce/2023/11/msg00017.html
• https://lists.debian.org/debian-lts-announce/2023/11/msg00030.html
• https://www.debian.org/security/2023/dsa-5561
• https://www.mozilla.org/security/advisories/mfsa2023-49/

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