CVE-2026-4693 involves incorrect boundary conditions in the Audio/Video Playback component of Mozilla Firefox. This vulnerability was identified and fixed by Mozilla in Firefox 149, Firefox ESR 115.34, and Firefox ESR 140.9. The flaw could cause a denial-of-service impact (availability) without affecting confidentiality or integrity. It is one of multiple high-impact security issues resolved in these versions, many related to memory safety and sandbox escapes. The vendor advisories confirm the fix and provide detailed references to the underlying bugs. No known exploits in the wild have been reported for this specific vulnerability.

The vulnerability can cause denial-of-service (availability impact) in affected Firefox versions prior to 149 and ESR versions prior to 115.34 and 140.9. There is no reported impact on confidentiality or integrity. The CVSS score is 7.5 (high), reflecting the potential to disrupt service but not to leak or alter data.

Mozilla has released official fixes for this vulnerability in Firefox 149, Firefox ESR 115.34, and Firefox ESR 140.9. Users and administrators should update to these versions or later to remediate the issue. Since this is not a cloud service, patching the client software is required. No additional mitigation steps are indicated by the vendor advisories.