VulnerabilityPublished 10 Nov 2026

CVE-2026-124939: JIT Miscompilation

Source GCVE Database

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Authoritative record:CVE-2026-124939· High

Not known to be exploited.

Data as of 10 Nov 2026, 17:20 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.

ghsa-hcwf-q2v7-rv7x

What to do

AI-suggested

Users and administrators should update to Firefox 160 or Firefox ESR 153.7 or later to remediate this vulnerability. The fix is officially released and available. No additional mitigation steps are indicated beyond applying the official update.

Description

CVE-2026-124939 is a vulnerability involving just-in-time (JIT) miscompilation in the JavaScript engine's JIT component. This flaw was addressed and fixed in Firefox 160 and Firefox ESR 153.7. The vulnerability is classified with high impact by Mozilla, indicating serious security concerns if left unpatched.

Impact

The vulnerability has a high impact rating according to Mozilla, suggesting it could lead to significant security issues if exploited. However, there are no known exploits in the wild reported. The flaw could affect the integrity or security of JavaScript execution within the browser.

Summary

This vulnerability relates to a miscompilation issue in the JIT component of the JavaScript engine used by Firefox. Such miscompilation could potentially lead to incorrect execution of JavaScript code. The issue was resolved in Firefox 160 and Firefox ESR 153.7. Mozilla has assigned a high impact rating to this vulnerability, reflecting the severity of the flaw. There is no indication of known exploitation in the wild at this time.

References

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