CVE-2026-92005

Published: Sep 15, 2026Updated: Sep 17, 2026 Sources: CVE List NVDCWE-416

5.3MEDIUM

NVD MITRE

Description

Use-after-free in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

In plain language

AI Act now

This can let someone crash Firefox or Thunderbird before version 156, or ESR 140.16 or 153.3; affected businesses should update promptly.

Executive summary

A network-reachable use-after-free in the Audio/Video: Web Codecs component permits unauthenticated remote denial of service through crafted content.

If affected, business impact

Browser or email client crashesStaff work interruptionLost unsaved workService desk workload

What to do now

Check the version and release channel of Firefox and Thunderbird installed on company computers.
Update standard releases to 156, or update the applicable ESR branch to 140.16 or 153.3.
If updates must wait, disable or restrict access to the Web Codecs feature where your managed configuration permits it, then schedule the update.

Usually a quick update

What is it

This is a flaw in the part of Firefox and Thunderbird that handles certain audio and video web content. It is like an application following an old address after the room behind that address has been cleared out, causing the application to fall over instead of continuing normally.

Who is affected

This matters to you if employees use Firefox or Thunderbird on business computers. An attacker does not need an account or employee action to trigger it; it is only a risk when the Audio/Video: Web Codecs component is enabled.

How urgent is it

Attackers can use crafted network content to crash affected applications remotely, making this a RED-priority update for organizations using the affected software. There is no confirmed active exploitation, no public exploit code on record, and no CISA Known Exploited Vulnerabilities listing, but do not defer the available fix.

What to do — in detail

Confirm exposure by inventorying Firefox and Thunderbird installations, including whether each is on the standard or ESR release channel, and checking whether the Audio/Video: Web Codecs component is enabled.

Upgrade standard-release Firefox and Thunderbird to 156. Upgrade the relevant ESR branch to 140.16 or 153.3; test the update through normal software-management controls before broad deployment if your organization pins browser or mail-client extensions.

If patching is delayed, use managed configuration or product controls to disable or limit Web Codecs where feasible, and reduce access to untrusted web content on affected endpoints. Monitor application crash reports and endpoint telemetry for unusual Firefox or Thunderbird crashes associated with crafted media or web content.

CISA has not listed this CVE in KEV, so there is no CISA remediation due date.

Technical context

CVE-2026-92005 is CWE-416 (use-after-free) in Audio/Video: Web Codecs, rated CVSS 5.3 (Medium) with network attack vector, low complexity, no privileges required, no user interaction, and availability impact limited to application denial of service. Findings describe remote crashes through crafted content when Web Codecs is enabled. It is not in CISA KEV, no clear dated in-the-wild exploitation claim is reported, and no public exploit code is on record. EPSS is 0.4% (32nd percentile) with a flat trend.

This is a general assessment based on public vulnerability data. It does not account for your specific infrastructure — when in doubt, consult a security specialist.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:NIntegrity

None

A:LAvailability

Low

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Weaknesses

CWE-416

Affected Products

Mozilla

oss-project·USaka mozilla corp.

FirefoxOn-premDesktop App

Consumer Software / browser

ThunderbirdOn-premDesktop App

Communications / email-server-client

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Is your org exposed to CVE-2026-92005?Request an assessment to establish which checks are appropriate for your systems. Check my exposure

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Initial Access

Privilege Escalation

View detailed technique mapping

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2056051

bugzilla.mozilla.org

https://www.mozilla.org/security/advisories/mfsa2026-90/

mozilla.org

https://www.mozilla.org/security/advisories/mfsa2026-92/

mozilla.org

and 4 more references View all →

News mentions

⚡ Weekly Recap: Cisco 0-Day, AI Agent RCE, ClickFix Attacks, ClickFix Surge, and Browser Hijacks
en·The Hacker News·Sep 21, 2026 Exploited Cisco Identity Services Engine zero-day

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