How do I check whether I am affected by CVE-2026-118016?

- Check the installed Firefox version in the browser's About page or with `firefox --version`, and compare it to `159`. - unknown for anything beyond the version check, since the sources do not say.

What is the fix for CVE-2026-118016?

- Update Firefox to `159` or later.

Who is not affected by CVE-2026-118016?

Not affected if: firefox-159-or-later.

Live › vulnerability › CVE-2026-118016

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unknownRuntime

Firefox: use-after-free in DOM core and HTML lets attackers run code

A use-after-free bug in Firefox's DOM Core and HTML component lets memory be reused after it is freed. The sources do not say what an attacker can do beyond that, and the fix ships in Firefox 159.

Summary written from the sources below. Check the originals before acting.

Known so far

3/6

unknown

no CVSS yet; severity from the sources

known so far3 of 6

missing: versions, primary source, exploitation

First public: Oct 27, 2026 UTC
Last modified: Oct 27, 2026
Status: open
Known exploitation: None reported
Public exploit: None on GitHub
EPSS: not scored

First seen by InfraStack 2026-10-27 14:32 UTC. All times on this page are UTC.

Why it is unknown, and not just CVSS

Likelihood → · Impact ↓

critical

high

medium

high

medium

low

medium

low

Exploited: No reports yet.
Needs login: Not known from the sources.
Needs a special setup: Not known from the sources.
Reachable from: Not known from the sources.
Worst case: Unknown; memory corruption could allow code execution.
CVSS said: No score. The facts above say medium; we keep the sources' unknown until an analyst looks.

Who is affected

Anyone running Firefox older than version 159 is likely exposed, since the sources say the flaw was fixed in that release. The sources do not say which configurations or content are needed to trigger it, so unknown beyond that.

Know the next one before it finds you.

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Live › vulnerability › CVE-2026-118016

Go to dashboard

unknownRuntime

Firefox: use-after-free in DOM core and HTML lets attackers run code

A use-after-free bug in Firefox's DOM Core and HTML component lets memory be reused after it is freed. The sources do not say what an attacker can do beyond that, and the fix ships in Firefox 159.

Summary written from the sources below. Check the originals before acting.

Known so far

3/6

unknown

no CVSS yet; severity from the sources

known so far3 of 6

missing: versions, primary source, exploitation

First public: Oct 27, 2026 UTC
Last modified: Oct 27, 2026
Status: open
Known exploitation: None reported
Public exploit: None on GitHub
EPSS: not scored

First seen by InfraStack 2026-10-27 14:32 UTC. All times on this page are UTC.

Why it is unknown, and not just CVSS

Likelihood → · Impact ↓

critical

high

medium

high

medium

low

medium

low

Exploited: No reports yet.
Needs login: Not known from the sources.
Needs a special setup: Not known from the sources.
Reachable from: Not known from the sources.
Worst case: Unknown; memory corruption could allow code execution.
CVSS said: No score. The facts above say medium; we keep the sources' unknown until an analyst looks.

Who is affected

Know the next one before it finds you.

Add to Slack

Firefox: use-after-free in DOM core and HTML lets attackers run code

Why it is unknown, and not just CVSS

Who is affected

Know the next one before it finds you.

Firefox: use-after-free in DOM core and HTML lets attackers run code

Why it is unknown, and not just CVSS

Who is affected

Know the next one before it finds you.

How to check

The fix

Who had it, and when

What the sources say, verbatim

Sources