CVE-2025-4918
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 9.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Details
- Published
- Last modified
- Exploit probability
- 9.5% · EPSS, next 30 days
- Weakness
- CWE-125 · Out-of-bounds read
- Record status
- Modified
Affected
- Mozilla Firefox < 115.23.1
- Mozilla Firefox < 138.0.4
- Mozilla Firefox < 128.10.1
- Mozilla Thunderbird < 128.10.2
- Mozilla Thunderbird < 138.0.2
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Fix and advisories
- https://www.mozilla.org/security/advisories/mfsa2025-36/
- https://www.mozilla.org/security/advisories/mfsa2025-37/
- https://www.mozilla.org/security/advisories/mfsa2025-38/
- https://www.mozilla.org/security/advisories/mfsa2025-40/
- https://www.mozilla.org/security/advisories/mfsa2025-41/
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1966612
- https://www.mozilla.org/security/advisories/mfsa2025-36/
- https://www.mozilla.org/security/advisories/mfsa2025-37/
- https://www.mozilla.org/security/advisories/mfsa2025-38/
- https://www.mozilla.org/security/advisories/mfsa2025-40/
- https://www.mozilla.org/security/advisories/mfsa2025-41/
- https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html
- https://lists.debian.org/debian-lts-announce/2025/05/msg00046.html
- https://www.vicarius.io/vsociety/posts/cve-2025-4918-detect-firefox-out-of-bounds-write
- https://www.vicarius.io/vsociety/posts/cve-2025-4918-mitigate-firefox-out-of-bounds-write