9.6

CVE-2026-92018: mozilla firefox Protection Mechanism Failure

CVSS: 9.6v3.1CriticalAnalyzed
AliasesUBUNTU-CVE-2026-92018DEBIAN-CVE-2026-92018
Published 15-09-2026Last modified 20-09-2026
Open JSON

Vulnerability summary

CVE-2026-92018 is a critical (CVSS 9.6) Protection Mechanism Failure vulnerability in mozilla firefox. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.5% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.6/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.33%
0%100%
Low · -0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 31 · Related 8
MGASA-2026-0441MGASA-2026-0449OPENSUSE-SU-2026:11796-1OPENSUSE-SU-2026:11826-1OPENSUSE-SU-2026:11827-1OPENSUSE-SU-2026:21951-1

Timeline

  1. 15-09-2026
    PublishedVulnerability first disclosed.
  2. 20-09-2026
    Last modifiedVulnerability information updated.

Description

Sandbox escape in the DOM: Core & HTML 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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.33%

Chance of exploitation in the next 30 days

Percentile

25%

Versus all other CVEs

30-day change

-0.02 pp

From 0.35% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.33%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

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)
Debian2 products
  • firefox-esr< 140.16.0esr-1~deb12u1 | < 140.16.0esr-1~deb13u1 | < 140.16.0esr-1
  • thunderbird< 1:140.16.0esr-1~deb12u1 | < 1:140.16.0esr-1~deb13u1 | < 1:153.3.0esr-1
Mozilla2 products
  • firefox< 115.41.0 | ≥ 116.0, < 140.16.0 | ≥ 141.0, < 153.3.0 | ≥ 154.0.0, < 156.0.0
  • thunderbird< 140.16.0 | ≥ 141.0, < 153.3.0 | ≥ 154.0, < 156.0

3 vendors · 12 products

References

12 links
Show all 12 references