# CVE-2026-117922 — Mozilla Firefox

> As of 2026-11-06, CVE-2026-117922 is a HIGH-severity vulnerability in Mozilla Firefox, CVSS v3.1 8.8, EPSS 0.3% (34.0th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-117922, most recently “OpenAI GPT-6 Cyber Identifies 81 Previously Unknown High-Severity Firefox Vulnerabilities (Mozilla MFSA2026-118, Firefox 159)”.

**Last updated:** 2026-11-04

## What is CVE-2026-117922?

Use-after-free in the Networking: WebSockets component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

The record classifies CVE-2026-117922 under weakness class [CWE-416](https://intel.threadlinqs.com/cwe/CWE-416). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity, availability. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 10 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 8.8 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 34.0% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 5.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-10-27, last modified 2026-11-04

## Is CVE-2026-117922 being exploited?

It currently carries a trending score of 41 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Mozilla](https://intel.threadlinqs.com/vendors/mozilla): Firefox, Thunderbird

## How to fix CVE-2026-117922

No vendor patch reference has been recorded for CVE-2026-117922 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-117922

1 tracked threat in the Threadlinqs corpus references CVE-2026-117922, either in the campaign’s CVE list or as an indicator on the campaign record.

- [OpenAI GPT-6 Cyber Identifies 81 Previously Unknown High-Severity Firefox Vulnerabilities (Mozilla MFSA2026-118, Firefox 159)](https://intel.threadlinqs.com/threat/TL-2026-5373) — HIGH · 2026-11-06

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-11-06. This product uses the NVD API but is not endorsed or certified by the NVD.

**Other references**

- [bugzilla.mozilla.org](https://bugzilla.mozilla.org/show_bug.cgi?id=2079692)
- [mozilla.org](https://www.mozilla.org/security/advisories/mfsa2026-118/)
- [mozilla.org (mfsa2026 119)](https://www.mozilla.org/security/advisories/mfsa2026-119/)
- [mozilla.org (mfsa2026 120)](https://www.mozilla.org/security/advisories/mfsa2026-120/)
- [mozilla.org (mfsa2026 121)](https://www.mozilla.org/security/advisories/mfsa2026-121/)

_Showing 5 of 6 recorded references._

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-117922
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