CVE-2025-4918

CRITICAL
Published May 17, 2025 Modified Apr 13, 2026 CWE-125 CWE-787

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.

CVSS v3.1 Score

9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-125 Out-of-bounds Read
CWE-787 Out-of-bounds Write

Affected Products

Vendor Product
mozilla firefox
mozilla firefox
mozilla firefox
mozilla thunderbird
mozilla thunderbird

References

Frequently Asked Questions

What is CVE-2025-4918? +
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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).
How severe is CVE-2025-4918? +
CVE-2025-4918 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.
What products are affected by CVE-2025-4918? +
CVE-2025-4918 affects products from mozilla, specifically: firefox, thunderbird. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-4918? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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