CVE-2025-8034
Published: 22 July 2025
Summary
CVE-2025-8034 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Mozilla Firefox. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked in the top 31.9% 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-16 (Memory Protection) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2025-8034 encompasses multiple memory safety bugs classified under CWE-119, affecting Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird ESR 128.12, Firefox ESR 140.0, Thunderbird ESR 140.0, Firefox 140, and Thunderbird 140. These bugs demonstrated evidence of memory corruption in some instances, which Mozilla presumes could be leveraged with sufficient effort to enable arbitrary code execution.
The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H), indicating it is exploitable remotely over the network with low attack complexity and no required privileges, though user interaction is necessary. Attackers could target end-users by luring them to malicious content, such as web pages or files processed by the browser or email client, potentially achieving arbitrary code execution within the affected application's sandboxed context and compromising confidentiality, integrity, and availability.
Mozilla has released patches addressing CVE-2025-8034 in Firefox 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird ESR 128.13, and Thunderbird ESR 140.1. Security advisories MFSA 2025-56, MFSA 2025-57, MFSA 2025-58, and MFSA 2025-59, along with Bugzilla entry 1970422, provide further technical details and mitigation guidance, emphasizing immediate updates for affected systems.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-22361
Vulnerability details
Memory safety bugs present in Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird ESR 128.12, Firefox ESR 140.0, Thunderbird ESR 140.0, Firefox 140 and Thunderbird 140. Some of these bugs showed evidence of memory corruption and we presume that with enough…
more
effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Memory corruption RCE in browser/email client directly enables client-side exploitation via malicious web content or files requiring user interaction.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Mandates timely flaw remediation through vulnerability scanning, patching, and updates, directly addressing the patched memory safety bugs in affected Firefox and Thunderbird versions.
Implements memory protection safeguards like ASLR and DEP to prevent exploitation of memory corruption bugs leading to arbitrary code execution.
Requires vulnerability scanning to identify systems running vulnerable Firefox ESR 115.25, 128.12, 140.0 or Thunderbird versions affected by this CVE.