CVE-2026-2773
Published: 24 February 2026
Summary
CVE-2026-2773 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 44.3th percentile by exploit likelihood (below the median); 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-2026-2773 is a high-severity vulnerability stemming from incorrect boundary conditions in the Web Audio component of Mozilla products. It affects Firefox versions prior to 148, Firefox ESR prior to 115.33 and 140.8, Thunderbird prior to 148 and 140.8. The issue is classified under CWE-119 (improper restriction of operations within the bounds of a memory buffer) with a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical risk due to its potential for severe impact.
A remote, unauthenticated attacker can exploit this vulnerability over the network with low complexity and no user interaction required. Successful exploitation enables high-impact compromise of confidentiality, integrity, and availability, likely allowing arbitrary code execution within the browser's rendering process via malicious web content, such as audio files or Web Audio API usage.
Mozilla has addressed the vulnerability in the specified fixed releases: Firefox 148, Firefox ESR 115.33 and 140.8, Thunderbird 148 and 140.8. Security advisories (MFSA 2026-13 through 16) and the Bugzilla entry (bug 2014832) detail the patches and recommend immediate upgrading to mitigate exposure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8494
Vulnerability details
Incorrect boundary conditions in the Web Audio component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Memory corruption RCE in browser rendering process via malicious web content (Web Audio) directly enables drive-by site exploitation and client application exploitation for code execution.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly addresses the CVE by requiring identification, prioritization, and timely patching of the buffer overflow flaw in affected Firefox and Thunderbird versions.
Implements memory protections that counter buffer overflow exploits (CWE-119) in the Web Audio component by enforcing non-executable memory and bounds checking.
Ensures receipt and implementation of Mozilla MFSA advisories specifying patches for this high-severity vulnerability.