CVE-2023-5173

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-09-27 · updated 2026-06-17
Weakness: CWE-190

Description

In a non-standard configuration of Firefox, an integer overflow could have occurred based on network traffic (possibly under influence of a local unprivileged webpage), leading to an out-of-bounds write to privileged process memory. *This bug only affects Firefox if a non-standard preference allowing non-HTTPS Alternate Services (`network.http.altsvc.oe`) is enabled.* This vulnerability affects Firefox < 118.

Affected products

Mozilla Firefox: before 118 — fixed in 118

How to fix

Upgrade to a fixed version: Mozilla Firefox 118. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1823172
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-41/
https://bugzilla.mozilla.org/show_bug.cgi?id=1823172
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-41/

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