VulnerabilityPublished 27 Oct 2026

CVE-2026-117866: Mozilla Firefox · Privilege escalation due to use-after-free in the Graphics: Canvas2D component

Affects Mozilla FirefoxSource CVE Database V5

Not known to be exploited.

Data as of 27 Oct 2026, 16:12 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Users and administrators should update Firefox to version 159 or later, or Firefox ESR versions 115.44 or 153.6 or later, where this vulnerability has been fixed. Applying these official updates fully mitigates the risk from this vulnerability.

Description

CVE-2026-117866 is a high-impact privilege escalation vulnerability caused by a use-after-free flaw in the Graphics: Canvas2D component of Mozilla Firefox. This vulnerability allows an attacker to escalate privileges within the browser environment. The issue was addressed and fixed in Firefox 159 and Firefox ESR versions 115.44 and 153.6.

Impact

Successful exploitation of this use-after-free vulnerability could allow an attacker to escalate privileges within the Firefox browser, potentially leading to unauthorized actions or code execution with elevated rights. The impact is rated high by the vendor.

Summary

This vulnerability involves a use-after-free condition in the Graphics: Canvas2D component of Firefox, which can be exploited to achieve privilege escalation. The flaw was reported to Mozilla and fixed in Firefox 159 and corresponding ESR releases. The Mozilla advisory lists this issue among multiple high-impact memory safety vulnerabilities resolved in the same update cycle. No public exploits or in-the-wild activity have been reported.

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 27 Oct 2026, 16:12 UTC

Technical details

References

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