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 (10)
Core 10
Core References
Permissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=1966612
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-36/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-37/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-38/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-40/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-41/
Exploit, Third Party Advisory
https://www.vicarius.io/vsociety/posts/cve-2025-4918-detect-firefox-out-of-bounds-write
Exploit, Third Party Advisory
https://www.vicarius.io/vsociety/posts/cve-2025-4918-mitigate-firefox-out-of-bounds-write
Scores
CVSS v3
9.8
EPSS
0.0099
EPSS Percentile
77.0%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
total
Details
CWE
CWE-125
CWE-787
Status
published
Products (9)
mozilla/firefox
< 115.23.1
mozilla/firefox
< 138.0.4
Mozilla/Firefox
115.23.1 - 115.*
Mozilla/Firefox
128.10.1 - 128.*
Mozilla/Firefox
138.0.4
mozilla/thunderbird
< 128.10.2
Mozilla/Thunderbird
128.10.2 - 128.*
mozilla/thunderbird
138.0 - 138.0.2
Mozilla/Thunderbird
138.0.2
Published
May 17, 2025
Tracked Since
Feb 18, 2026