CVE-2026-16394: Mitigation bypass in the DOM: Security component

Q: How do I fix CVE-2026-16394?

firefox: upgrade to 153.0.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-16394 being exploited?

CVE-2026-16394 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-16394 affect?

CVE-2026-16394 affects firefox. Severity is critical (CVSS 9.1). Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

Q: How urgent is CVE-2026-16394?

Priority 41/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-16394 is a critical-severity flaw (CVSS 9.1) affecting firefox. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 84%)
CISA exploited list	No
Weakness	CWE-693
Published	2026-07-21
Last modified	2026-10-24

Publisher (CNA): Mozilla Corporation · Vendor: mozilla

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-21 13:17 UTCPublished CVE record published
2026-10-24 20:10 UTCUpdated Record last modified

mozilla firefox UPGRADE

Affected: < 153.0.0

Fixed in: 153.0.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy firefox || rpm -q firefox || firefox --version

2. UPGRADE to 153.0.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade firefox

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade firefox

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-16394?

firefox: upgrade to 153.0.0. Exact commands for each OS are on this page.

Is CVE-2026-16394 being exploited?

CVE-2026-16394 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-16394 affect?

CVE-2026-16394 affects firefox. Severity is critical (CVSS 9.1). Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

How urgent is CVE-2026-16394?

Priority 41/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

Mozilla Firefox vulnerabilities · Mozilla Thunderbird vulnerabilities

Related CVEs

CVE-2026-16389 CRITICAL 9.8 UPGRADE UPGRADE Incorrect boundary conditions, integer overflow in the Libraries component in NSS
CVE-2026-16353 CRITICAL 9.8 UPGRADE UPGRADE Invalid pointer in the DOM: Bindings (WebIDL) component
CVE-2026-16360 CRITICAL 9.8 UPGRADE UPGRADE Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152
CVE-2026-16363 CRITICAL 9.8 UPGRADE UPGRADE JIT miscompilation in the JavaScript: WebAssembly component
CVE-2026-16369 CRITICAL 9.8 UPGRADE UPGRADE Integer overflow in the JavaScript: WebAssembly component

References

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