An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object. This vulnerability affects Firefox < 138.0.4, Firefox ESR < 128.10.1, Firefox ESR < 115.23.1, Thunderbird < 128.10.2, and Thunderbird < 138.0.2.
https://www.bleepingcomputer.com/news/security/mozilla-fixes-firefox-zero-days-exploited-at-hacking-contest/
https://thehackernews.com/2025/05/firefox-patches-2-zero-days-exploited.html
https://securityaffairs.com/178064/security/mozilla-fixed-zero-days-demonstrated-at-pwn2own-berlin-2025.html
https://www.mozilla.org/security/advisories/mfsa2025-41/
https://www.mozilla.org/security/advisories/mfsa2025-40/
https://www.mozilla.org/security/advisories/mfsa2025-38/
https://www.mozilla.org/security/advisories/mfsa2025-37/
https://www.mozilla.org/security/advisories/mfsa2025-36/
https://bugzilla.mozilla.org/show_bug.cgi?id=1966612
Source: Mitre, NVD
Published: 2025-05-17
Updated: 2025-05-28
Base Score: 10
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
Severity: Critical
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Severity: High
EPSS: 0.00018