CVE-2025-4918

CRITICAL 9.8CVE-2025-4918 · Published 17/05/2025 · updated 30/09/2026

Package	Affected versions	Patched versions
firefox mozilla	`≥ 116.0, < 128.10.1< 115.23.1< 138.0.4`	`128.10.1115.23.1138.0.4`
thunderbird mozilla	`≥ 138.0, < 138.0.2< 128.10.2`	`138.0.2128.10.2`

Description

An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object. This vulnerability was fixed in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.

References

bugzilla.mozilla.org/show_bug.cgi · Permissions Required
mozilla.org/security/advisories/mfsa2025-36 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-37 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-38 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-40 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-41 · Vendor Advisory
lists.debian.org/debian-lts-announce/2025/05/msg00024.html
lists.debian.org/debian-lts-announce/2025/05/msg00046.html
vicarius.io/vsociety/posts/cve-2025-4918-detect-firefox-out-of-bounds-write · Exploit
vicarius.io/vsociety/posts/cve-2025-4918-mitigate-firefox-out-of-bounds-write · Exploit

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