Firefox vulnerability

Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox ESR 140.16 and Thunderbird 140.16.

Published 15 Sep 2026Updated 6 Oct 20263 sources
CVSS 8.8

What happened

Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox ESR 140.16 and Thunderbird 140.16.

Affected versions

Firefox: before 140.16.0 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.