CVE-2025-1942
CRITICALCVSS 9.8/10EPSS 0.45%
Last modified
CVE-2025-1942 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 0.45% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 136.0 |
| Mozilla | Thunderbird | < 136.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1947139Issue Tracking
- https://www.mozilla.org/security/advisories/mfsa2025-14/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-17/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
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.
How severe is CVE-2025-1942?
CVE-2025-1942 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.45% probability of exploitation in the next 30 days.
How do I fix CVE-2025-1942?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2025
- CVE-2025-1936jar: URLs retrieve local file content packaged in a ZIP arch…7.3
- CVE-2025-1937Memory safety bugs present in Firefox 135, Thunderbird 135, …7.5
- CVE-2025-1938Memory safety bugs present in Firefox 135, Thunderbird 135, …6.5
- CVE-2025-1939Android apps can load web pages using the Custom Tabs featur…3.9
- CVE-2025-1940A select option could partially obscure the confirmation pro…7.1
- CVE-2025-1941Under certain circumstances, a user opt-in setting that Focu…9.1
- CVE-2025-1943Memory safety bugs present in Firefox 135 and Thunderbird 13…8.2
- CVE-2025-1944picklescan before 0.0.23 is vulnerable to a ZIP archive mani…6.5
- CVE-2025-1945picklescan before 0.0.23 fails to detect malicious pickle fi…9.8
- CVE-2025-1946A vulnerability was found in hzmanyun Education and Training…9.8
- CVE-2025-1947A vulnerability classified as critical has been found in hzm…9.8
- CVE-2025-1948In Eclipse Jetty versions 12.0.0 to 12.0.16 included, an HTT…7.5
Are you affected by CVE-2025-1942?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST