CVE-2026-2788
Published: 24 February 2026
Summary
CVE-2026-2788 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 7.0th 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-2 (Flaw Remediation) and SC-39 (Process Isolation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly addresses the vulnerability by requiring timely identification, testing, and installation of patches for the GMP buffer overflow flaw in affected Firefox and Thunderbird versions.
Mitigates buffer overflow exploitation through memory protections like ASLR, DEP, and stack canaries, reducing the likelihood of arbitrary code execution from malicious media.
Enforces process isolation for the GMP media decoding component, containing potential exploits to prevent full system compromise.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Buffer overflow in client-side media decoder (GMP) enables RCE on Firefox/Thunderbird via malicious audio/video with no user interaction, directly mapping to drive-by compromise and client exploitation techniques.
NVD Description
Incorrect boundary conditions in the Audio/Video: GMP component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Deeper analysisAI
CVE-2026-2788 is a high-severity vulnerability stemming from incorrect boundary conditions in the Audio/Video: GMP (Gonk Media Plugin) component used by Mozilla products for media decoding. 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 an additional NVD-CWE-noinfo mapping, earning a CVSS v3.1 base score of 9.8.
The vulnerability enables remote attackers to exploit it over the network with low complexity, requiring no privileges or user interaction. Successful exploitation grants high-impact confidentiality, integrity, and availability violations, potentially allowing arbitrary code execution, data theft, or system compromise when processing malicious audio or video content via the GMP component.
Mozilla security advisories (MFSA 2026-13 through 2026-16) and the associated Bugzilla entry (2014824) confirm the issue was addressed in the listed fixed releases. Security practitioners should prioritize updating affected Firefox and Thunderbird installations to mitigate the risk, as no workarounds are detailed in the provided references.
Details
- CWE(s)