The vulnerability identified as CVE-2026-100797 involves a use-after-free condition in the Graphics: WebRender component of Mozilla Firefox. This flaw enables privilege escalation, potentially allowing an attacker to gain elevated rights within the affected system. Mozilla has fixed this issue in multiple Firefox ESR versions (115.42, 140.17, 153.4) and Firefox 157. The vendor advisory confirms the fix and classifies the impact as high. There are no reports of active exploitation in the wild.

Successful exploitation of this use-after-free vulnerability could lead to privilege escalation, granting an attacker higher-level access than intended. This could compromise the security context of the Firefox process and potentially the underlying system. However, no active exploitation has been observed.

This vulnerability has been fixed by Mozilla in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. Users and administrators should update to these versions or later to mitigate the risk. No additional mitigation steps are required beyond applying the official patches.