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.
History

Mon, 13 Apr 2026 15:00:00 +0000

Type Values Removed Values Added
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 affects Firefox < 136 and Thunderbird < 136. 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.
Title firefox: Disclosure of uninitialized memory when .toUpperCase() causes string to get longer Disclosure of uninitialized memory when .toUpperCase() causes string to get longer

Fri, 28 Mar 2025 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
Vendors & Products Mozilla
Mozilla firefox
Mozilla thunderbird

Tue, 25 Mar 2025 14:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-908
Metrics cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 12 Mar 2025 17:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-908
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L'}


Wed, 05 Mar 2025 03:00:00 +0000

Type Values Removed Values Added
Title firefox: Disclosure of uninitialized memory when .toUpperCase() causes string to get longer
Weaknesses CWE-824
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 05 Mar 2025 00:00:00 +0000

Type Values Removed Values Added
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 affects Firefox < 136. When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string This vulnerability affects Firefox < 136 and Thunderbird < 136.
References

Tue, 04 Mar 2025 16:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-908
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 04 Mar 2025 13:45:00 +0000

Type Values Removed Values Added
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 affects Firefox < 136.
References

cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-04-13T14:30:28.192Z

Reserved: 2025-03-04T12:29:51.191Z

Link: CVE-2025-1942

cve-icon Vulnrichment

Updated: 2025-03-04T15:45:14.531Z

cve-icon NVD

Status : Modified

Published: 2025-03-04T14:15:39.167

Modified: 2026-04-13T15:16:53.940

Link: CVE-2025-1942

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-03-04T13:31:25Z

Links: CVE-2025-1942 - Bugzilla