CVE-2026-4692
published 2026-03-24CVE-2026-4692: 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…
PriorityP354critical10CVSS 3.1
AVNACLPRNUINSCCHIHAH
EPSS
0.49%
38.7th percentile
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.
Affected
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| debian | firefox-esr | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| debian | thunderbird | < firefox 149.0-1 (sid) | firefox 149.0-1 (sid) |
| mozilla | firefox | < 115.34.0 | 115.34.0 |
| mozilla | firefox | < 149.0 | 149.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 128.0 < 140.9.0 | 140.9.0 |
| mozilla | thunderbird | < 140.9.0 | 140.9.0 |
| mozilla | thunderbird | < 149.0 | 149.0 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb11u1 | 1:140.9.0esr-1~deb11u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb12u1 | 1:140.9.0esr-1~deb12u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1~deb13u1 | 1:140.9.0esr-1~deb13u1 |
| mozilla | thunderbird | >= 0 < 1:140.9.0esr-1 | 1:140.9.0esr-1 |
CVSS provenance
nvdv3.110.0CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
osv10.0CRITICAL
vendor_debian10.0CRITICAL
vendor_redhat10.0CRITICAL
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VulDB
Mozilla Firefox up to 148 Design Mode sandbox (Nessus ID 304234 / WID-SEC-2026-0850)
vuldb·2026-04-16·CVSS 10.0
CVE-2026-4692 [CRITICAL] Mozilla Firefox up to 148 Design Mode sandbox (Nessus ID 304234 / WID-SEC-2026-0850)
A vulnerability identified as critical has been detected in Mozilla Firefox up to 148. This affects an unknown part of the component Design Mode. The manipulation leads to sandbox issue.
This vulnerability is traded as CVE-2026-4692. It is possible to initiate the attack remotely. There is no exploit available.
You should upgrade the affected component.
GHSA
GHSA-cm3f-xp4p-xgj7: Sandbox escape in the Responsive Design Mode component
ghsa_unreviewed·2026-03-24
CVE-2026-4692 [CRITICAL] GHSA-cm3f-xp4p-xgj7: Sandbox escape in the Responsive Design Mode component
Sandbox escape in the Responsive Design Mode component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.
OSV
CVE-2026-4692: Sandbox escape in the Responsive Design Mode component
osv·2026-03-24·CVSS 10.0
CVE-2026-4692 [CRITICAL] CVE-2026-4692: Sandbox escape in the Responsive Design Mode component
Sandbox escape in the Responsive Design Mode component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Red Hat
firefox: thunderbird: Sandbox escape in the Responsive Design Mode component
vendor_redhat·2026-03-24·CVSS 10.0
CVE-2026-4692 [CRITICAL] CWE-653 firefox: thunderbird: Sandbox escape in the Responsive Design Mode component
firefox: thunderbird: Sandbox escape in the Responsive Design Mode component
Sandbox escape in the Responsive Design Mode component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Sandbox escape in the Responsive Design Mode component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: th
Debian
CVE-2026-4692: firefox - Sandbox escape in the Responsive Design Mode component. This vulnerability affec...
vendor_debian·2026·CVSS 10.0
CVE-2026-4692 [CRITICAL] CVE-2026-4692: firefox - Sandbox escape in the Responsive Design Mode component. This vulnerability affec...
Sandbox escape in the Responsive Design Mode component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Scope: local
sid: resolved (fixed in 149.0-1)
Mozilla
Mozilla Foundation Security Advisory 2026-20: CVE-2026-4692
vendor_mozilla·CVSS 10.0
CVE-2026-4692 [CRITICAL] Mozilla Foundation Security Advisory 2026-20: CVE-2026-4692
Mozilla Foundation Security Advisory 2026-20
CVE: CVE-2026-4692
Product: Firefox
Impact: high
Fixed in: Firefox 149
Mozilla
Mozilla Foundation Security Advisory 2026-23: CVE-2026-4692
vendor_mozilla·CVSS 10.0
CVE-2026-4692 [CRITICAL] Mozilla Foundation Security Advisory 2026-23: CVE-2026-4692
Mozilla Foundation Security Advisory 2026-23
CVE: CVE-2026-4692
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 149
Mozilla
Mozilla Foundation Security Advisory 2026-24: CVE-2026-4692
vendor_mozilla·CVSS 10.0
CVE-2026-4692 [CRITICAL] Mozilla Foundation Security Advisory 2026-24: CVE-2026-4692
Mozilla Foundation Security Advisory 2026-24
CVE: CVE-2026-4692
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.9
Mozilla
Mozilla Foundation Security Advisory 2026-22: CVE-2026-4692
vendor_mozilla·CVSS 10.0
CVE-2026-4692 [CRITICAL] Mozilla Foundation Security Advisory 2026-22: CVE-2026-4692
Mozilla Foundation Security Advisory 2026-22
CVE: CVE-2026-4692
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.9
Mozilla
Mozilla Foundation Security Advisory 2026-21: CVE-2026-4692
vendor_mozilla·CVSS 10.0
CVE-2026-4692 [CRITICAL] Mozilla Foundation Security Advisory 2026-21: CVE-2026-4692
Mozilla Foundation Security Advisory 2026-21
CVE: CVE-2026-4692
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.34
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-4692 firefox: thunderbird: Sandbox escape in the Responsive Design Mode component
bugzilla·2026-03-24·CVSS 10.0
CVE-2026-4692 [CRITICAL] CVE-2026-4692 firefox: thunderbird: Sandbox escape in the Responsive Design Mode component
CVE-2026-4692 firefox: thunderbird: Sandbox escape in the Responsive Design Mode component
Sandbox escape in the Responsive Design Mode component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:5931 https://access.redhat.com/errata/RHSA-2026:5931
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:5930 https://access.redhat.com/errata/RHSA-2026:5930
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:5932 https://access.redhat.com/errata/RHSA-2026:5932
---
This issue has been addressed in the following products:
Red Hat Enter
Wiz
CVE-2026-4692 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 7.5
CVE-2026-4692 [HIGH] CVE-2026-4692 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-4692 :
NixOS vulnerability analysis and mitigation
Sandbox escape in the Responsive Design Mode component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
Source : NVD
## 10
Score
Published March 24, 2026
Severity CRITICAL
CNA Score 9.6
Affected Technologies
NixOS
Mozilla Firefox
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 7
Exploitation Probability (EPSS) N/A
Affected packages and libraries
firefox
firefox-x11
Sources
AlmaLinux 8 Severity HIGH Has Fix Added at: Mar 31, 2026
AlmaLinux 9 Severity HIGH Has Fix Added at: Mar 31, 2026
Chainguard Has Fix Added at: Mar 29, 2026
Debian 1
https://bugzilla.mozilla.org/show_bug.cgi?id=2017643https://www.mozilla.org/security/advisories/mfsa2026-20/https://www.mozilla.org/security/advisories/mfsa2026-21/https://www.mozilla.org/security/advisories/mfsa2026-22/https://www.mozilla.org/security/advisories/mfsa2026-23/https://www.mozilla.org/security/advisories/mfsa2026-24/https://access.redhat.com/errata/RHSA-2026:5930https://access.redhat.com/errata/RHSA-2026:5931https://access.redhat.com/errata/RHSA-2026:5932https://access.redhat.com/errata/RHSA-2026:6188https://access.redhat.com/errata/RHSA-2026:6342https://access.redhat.com/errata/RHSA-2026:6917https://access.redhat.com/errata/RHSA-2026:7837https://access.redhat.com/errata/RHSA-2026:7838https://access.redhat.com/errata/RHSA-2026:7839https://access.redhat.com/errata/RHSA-2026:7840https://access.redhat.com/errata/RHSA-2026:7841https://access.redhat.com/errata/RHSA-2026:7842https://access.redhat.com/errata/RHSA-2026:7843https://access.redhat.com/errata/RHSA-2026:7845https://access.redhat.com/errata/RHSA-2026:7858https://access.redhat.com/errata/RHSA-2026:8284https://access.redhat.com/errata/RHSA-2026:8285https://access.redhat.com/errata/RHSA-2026:8286https://access.redhat.com/errata/RHSA-2026:8287https://access.redhat.com/errata/RHSA-2026:8288https://access.redhat.com/errata/RHSA-2026:8289https://access.redhat.com/errata/RHSA-2026:8290https://access.redhat.com/errata/RHSA-2026:8315https://access.redhat.com/errata/RHSA-2026:8427https://access.redhat.com/errata/RHSA-2026:8850https://access.redhat.com/security/cve/CVE-2026-4692https://bugzilla.redhat.com/show_bug.cgi?id=2450748https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4692.json
2026-03-24
Published