CVE-2023-5722

Severity: medium (CVSS 5.3 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: 2023-10-25 · updated 2026-06-17
Weakness: CWE-203

Description

Using iterative requests an attacker was able to learn the size of an opaque response, as well as the contents of a server-supplied Vary header. This vulnerability affects Firefox < 119.

Affected products

Mozilla Firefox: before 119.0 — fixed in 119.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 119.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1738426
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-45/
https://bugzilla.mozilla.org/show_bug.cgi?id=1738426
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-45/

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