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CVE-2026-4692: Sandbox escape in the Responsive Design Mode component

Modified
AliasesUBUNTU-CVE-2026-4692DEBIAN-CVE-2026-4692CGA-9g99-mxqc-v6vq
Published 24-03-2026Last modified 15-07-2026

Vulnerability summary

CVE-2026-4692 is a critical (CVSS 10.0) vulnerability in mozilla firefox. EPSS estimates a 0.51% chance of exploitation in the next 30 days, higher than 43.2% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.6 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
10.0/10
010
Critical · v3.1 (NVD)
EPSS score
0.51%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 39 · Related 9
DLA-4510-1DLA-4511-1DSA-6178-1DSA-6179-1MGASA-2026-0080MGASA-2026-0081

Timeline

  1. 24-03-2026
    PublishedVulnerability first disclosed.
  2. 15-07-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.51%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

Increase +0.02 pp

From 0.49% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu8 products
  • mozjs102All versions (No fix recorded)
  • mozjs115All versions (No fix recorded)
  • mozjs38All versions (No fix recorded)
  • mozjs52All versions (No fix recorded)
  • mozjs68All versions (No fix recorded)
Chainguard2 products
  • firefox< 149.0-r0
  • firefox-esr< 140.9-r0
Debian2 products
  • firefox-esr< 140.9.0esr-1~deb12u1 | < 140.9.0esr-1~deb13u1 | < 140.9.0esr-1
  • thunderbird< 1:140.9.0esr-1~deb12u1 | < 1:140.9.0esr-1~deb13u1 | < 1:140.9.0esr-1
Mozilla2 products
Wolfi1 product
  • firefox< 149.0-r0

5 vendors · 15 products

References

40 links
Show all 40 references