Firefox vulnerability

Use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

Published 15 Sep 2026Updated 6 Oct 20268 sources
CVSS 8.8

What happened

Use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

Affected versions

Firefox: before 115.41.0; 116.0 through before 140.16.0; 141.0 through before 153.3.0; 154.0.0 through before 156.0.0; before 140.16.0; 154.0 through before 156.0 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.