CVE-2024-5699

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2024-06-11 · updated 2026-06-17
Weakness: CWE-178

Description

In violation of spec, cookie prefixes such as `__Secure` were being ignored if they were not correctly capitalized - by spec they should be checked with a case-insensitive comparison. This could have resulted in the browser not correctly honoring the behaviors specified by the prefix. This vulnerability affects Firefox < 127.

Affected products

Mozilla Firefox: before 127.0 — fixed in 127.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 127.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1891349
https://www.mozilla.org/security/advisories/mfsa2024-25/
https://bugzilla.mozilla.org/show_bug.cgi?id=1891349
https://www.mozilla.org/security/advisories/mfsa2024-25/

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