CVE-2025-4918

9.8 CRITICAL

Published: May 17, 2025 Modified: November 03, 2025

Description

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

CVSS v3.x Details

0.0 Low Medium High Critical 10.0

Vector String

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory

https://bugzilla.mozilla.org/show_bug.cgi?id=1966612

Source: security@mozilla.org

Permissions Required

https://www.mozilla.org/security/advisories/mfsa2025-36/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-37/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-38/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-40/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-41/

Source: security@mozilla.org

Vendor Advisory

https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html

Source: af854a3a-2127-422b-91ae-364da2661108

https://lists.debian.org/debian-lts-announce/2025/05/msg00046.html

Source: af854a3a-2127-422b-91ae-364da2661108

https://www.vicarius.io/vsociety/posts/cve-2025-4918-detect-firefox-out-of-bounds-write

Source: af854a3a-2127-422b-91ae-364da2661108

Exploit Third Party Advisory

https://www.vicarius.io/vsociety/posts/cve-2025-4918-mitigate-firefox-out-of-bounds-write

Source: af854a3a-2127-422b-91ae-364da2661108

Exploit Third Party Advisory

10 reference(s) from NVD

Quick Stats

CVSS v3 Score

9.8 / 10.0

EPSS (Exploit Probability)

0.1%

32th percentile

Exploitation Status

Not in CISA KEV

Weaknesses (CWE)

CWE-125 CWE-787

Affected Vendors

mozilla

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