CVE-2026-6783
Published: 21 April 2026
Summary
CVE-2026-6783 is a medium-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Mozilla Firefox. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 11.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Integer overflow in browser media component enables remote exploitation via malicious content (web/email) for client execution or drive-by compromise, though limited to low-integrity impact per description.
NVD Description
Incorrect boundary conditions, integer overflow in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.
Deeper analysisAI
CVE-2026-6783 is an integer overflow vulnerability stemming from incorrect boundary conditions (CWE-190) in the Audio/Video Playback component of Mozilla Firefox and Thunderbird. The issue allows improper handling of data during media playback processing, which was addressed in Firefox version 150 and Thunderbird version 150.
The vulnerability carries a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N), indicating it is exploitable over the network with low complexity, requiring no privileges, no user interaction, and no change in scope. Remote unauthenticated attackers can trigger the integer overflow by supplying malicious media content, potentially leading to limited integrity impacts such as unexpected data modification without affecting confidentiality or availability.
Mozilla's security advisories (MFSA 2026-30 and MFSA 2026-33) and the associated Bugzilla entry (bug 2027564) detail the patch deployment in Firefox 150 and Thunderbird 150, recommending immediate updates to affected versions as the primary mitigation. No workarounds are specified in the provided references.
Details
- CWE(s)