CVE-2026-100783 is a vulnerability involving uninitialized memory in the Audio/Video component of Firefox. This issue was addressed and fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. The vulnerability has a CVSS score of 4.3, indicating a medium severity level, and it impacts availability but not confidentiality or integrity. No known exploits are reported in the wild.