CVE-2025-1942

Description

When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string. This vulnerability was fixed in Firefox 136 and Thunderbird 136.

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-908 CWE-908

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 136.0
mozilla	thunderbird	< 136.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-14/ https://www.mozilla.org/security/advisories/mfsa2025-17/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1947139

Frequently Asked Questions

What is CVE-2025-1942? +

When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string. This vulnerability was fixed in Firefox 136 and Thunderbird 136. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2025-1942? +

CVE-2025-1942 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-2025-1942? +

CVE-2025-1942 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-2025-1942? +

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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