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CVE-2025-4918Out-of-bounds access when resolving Promise objects
- 9.8CriticalCVSS base score
- 9.5%Exploitation in 30 daysEPSS · top 4.5% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mozilla
Published
- 11 months later
· 11 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 9.5% · top 4.5% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- unaffected 115.23.1 – ≤ 115.*
- unaffected 128.10.1 – ≤ 128.*
- unaffected 138.0.4 – ≤ *
- unaffected 128.10.2 – ≤ 128.*
- unaffected 138.0.2 – ≤ *
References
References10
- https://bugzilla.mozilla.org/show_bug.cgi?id=1966612 (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-36/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-37/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-38/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-40/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-41/ (opens in a new tab)
- https://www.vicarius.io/vsociety/posts/cve-2025-4918-detect-firefox-out-of-bounds-write (opens in a new tab)
- https://www.vicarius.io/vsociety/posts/cve-2025-4918-mitigate-firefox-out-of-bounds-write (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/05/msg00046.html (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-15599 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-4918)Record last updated .