CVE-2026-16394: Mitigation bypass in the DOM: Security component
Modified
AliasesUBUNTU-CVE-2026-16394CGA-6jm8-cwx2-2rxhCGA-992f-r46g-r329CGA-c8qq-6436-89f9CGA-qpwg-7vrj-9c93
Published 21-07-2026Last modified 22-07-2026
Vulnerability summary
CVE-2026-16394 is a critical (CVSS 9.1) Protection Mechanism Failure vulnerability in mozilla firefox. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.4% of scored vulnerabilities.
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)EPSS score
0.25%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 8 · Related 9Timeline
- 21-07-2026PublishedVulnerability first disclosed.
- 22-07-2026Last modifiedVulnerability information updated.
Description
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.
CVSS metrics
3 scores · 3 sources · 1 versionCritical 9.1Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- NVDNIST9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.25%
Chance of exploitation in the next 30 days
Percentile
15%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.25% on 22-09-2026
22-09-202622-10-2026
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected 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)
Chainguard2 products
- firefox< 153.0-r0
- firefox-docker-selenium-compat< 153.0-r0
Wolfi2 products
- firefox< 153.0-r0
- firefox-docker-selenium-compat< 153.0-r0
Mozilla1 product
- firefox< 153.0.0
4 vendors · 13 products
References
6 links- bugzilla.mozilla.org/show_bug.cgi?id=2046748Permissions Required
- www.mozilla.org/security/advisories/mfsa2026-68/Vendor Advisory