CVE-2025-4918: An attacker was able to perform an out-of-bounds read or write on a JavaScript Promise object
Source GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 29 Oct 2026, 22:52 UTC
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 18 May 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
Description
An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object. This vulnerability affects Firefox ESR < 115.23.1.
References
- nvd.nist.gov/vuln/detail/CVE-2025-4918 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1966612 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/05/msg00024.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/05/msg00046.html (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-36 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-37 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-38 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-40 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-41 (opens in a new tab)
- vicarius.io/vsociety/posts/cve-2025-4918-detect-firefox-out-of-bounds-write (opens in a new tab)
- vicarius.io/vsociety/posts/cve-2025-4918-mitigate-firefox-out-of-bounds-write (opens in a new tab)