🛡️ CVE-2026-4692 — firefox
Description
Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability high.
Affected software
CVE-2026-4692 is recorded against 2 packages.
- firefox (from 128.0 up to 140.9.0)
- thunderbird (fixed in 149.0)
Timeline and source
Published on 24 March 2026 and last revised on 15 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.
References
bugzilla.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
CVE-2026-4692 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| firefox | 128.0 | 140.9.0 |
| thunderbird | — | 149.0 |
References
Similar Threats
- Unknown ALSA-2022:8580
- Unknown ALSA-2022:8554
- Unknown ALSA-2022:7070
- Unknown ALSA-2022:7071
- Unknown ALSA-2022:7020
More CVE 2026 advisories
Browse all of CVE 2026 in the advisory index.
Exploit Protection
Are you running firefox?
CVE-2026-4692 carries CVSS 10.0 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.
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