🛡️ CVE-2025-4918 — firefox

🔴 CVSS 9.8 — Critical ⚠️ Exploit Public CWE-125 NVD
9.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2025-4918 is classified as CWE-125: Out-of-bounds Read. The code reads past the limits of a buffer, exposing adjacent memory contents or crashing the process.

Affected software

CVE-2025-4918 is recorded against 2 packages.

  • firefox (from 116.0 up to 128.10.1)
  • thunderbird (from 138.0 up to 138.0.2)

Timeline and source

Published on 17 May 2025 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

bugzilla.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org
lists.debian.org
lists.debian.org
www.vicarius.io
www.vicarius.io

CVE-2025-4918 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity CRITICAL
CVSS Score 9.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-125
Public Exploit ⚠️ Yes
Source NVD
Published 2025-05-17
Updated 2026-08-11
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
firefox 116.0 128.10.1
thunderbird 138.0 138.0.2

References

Similar Threats

Exploit Protection

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CVE-2025-4918 carries CVSS 9.8 Critical rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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