VulnerabilityPublished 10 Nov 2026

CVE-2026-124950: Mozilla Firefox · Same-origin policy bypass in the CSS Parsing and Computation component

Affects Mozilla FirefoxSource CVE Database V5

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Not known to be exploited.

Data as of 10 Nov 2026, 13:36 UTC

Severity

High

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

Thin evidence

One scorer or none

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 10 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Affected software

Product	Affected	Fixed in
Mozilla Firefox	Affected <160	Fixed in 160

AI-suggested

This vulnerability has been fixed in Firefox 160. Users and administrators should update to Firefox 160 or later to remediate this issue. No additional mitigation steps are required beyond applying the official update.

Description

CVE-2026-124950 is a same-origin policy bypass vulnerability in the CSS Parsing and Computation component of Mozilla Firefox. This security flaw allows bypassing the same-origin policy, which is a critical browser security mechanism. The vulnerability was fixed in Firefox version 160. The impact of this vulnerability is considered high. No public exploit code or in-the-wild exploitation has been reported.

Impact

Bypassing the same-origin policy can allow an attacker to access or manipulate resources and data from another origin, potentially leading to unauthorized data disclosure or manipulation within the browser context. This undermines the browser's security model and can facilitate further attacks such as cross-site scripting or data theft. The vendor rates the impact as high.

Summary

This vulnerability involves a bypass of the same-origin policy within the CSS Parsing and Computation component of Firefox. The same-origin policy is fundamental to web security, preventing malicious scripts on one origin from accessing data on another. The flaw was addressed and fixed in Firefox 160 as part of a broader security update that resolved multiple high-impact vulnerabilities. The vendor advisory confirms the fix and classifies the impact as high.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Nov 2026, 13:36 UTC

Technical details

References

Community reviews

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