CVE-2025-1943
Published: 04 March 2025
Summary
CVE-2025-1943 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Mozilla Firefox. Its CVSS base score is 8.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 41.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and SI-5 (Security Alerts, Advisories, and Directives).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly requires timely identification, reporting, and patching of the memory safety bugs in Firefox 135 and Thunderbird 135 as fixed in versions 136.
Mandates obtaining and implementing security advisories like Mozilla's MFSA 2025-14 and MFSA 2025-17 to address this vulnerability through patching.
Deploys memory protection mechanisms such as ASLR and DEP to mitigate exploitation of heap-based buffer overflows leading to potential arbitrary code execution.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Heap-based buffer overflow enabling remote arbitrary code execution in client applications (browser/email client) without user interaction directly maps to Exploitation for Client Execution.
NVD Description
Memory safety bugs present in Firefox 135 and Thunderbird 135. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was…
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fixed in Firefox 136 and Thunderbird 136.
Deeper analysisAI
CVE-2025-1943 is a set of memory safety bugs (classified under CWE-122, heap-based buffer overflow) affecting Firefox 135 and Thunderbird 135. These bugs exhibited evidence of memory corruption, which Mozilla presumes could be exploited with sufficient effort to achieve arbitrary code execution. The vulnerability carries a CVSS v3.1 base score of 8.2 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H), highlighting its high severity due to network accessibility and low attack complexity.
Remote attackers can exploit this vulnerability without authentication, privileges, or user interaction, potentially leading to memory corruption and, with advanced techniques, arbitrary code execution on affected systems. The impact primarily targets availability (high) and integrity (low), with no direct confidentiality loss, making it suitable for denial-of-service or code injection scenarios in browser or email client contexts.
Mozilla's security advisories (MFSA 2025-14 and MFSA 2025-17) and associated Bugzilla entries detail the fixes implemented in Firefox 136 and Thunderbird 136. Security practitioners should prioritize updating to these patched versions to mitigate the risks, as no workarounds are specified in the provided references.
Details
- CWE(s)