CVE-2026-8389: Mozilla Firefox · CWE-686
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 8.8 High : upgrade to 150.0.3 soon.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 150.0.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
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), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade mozilla/firefox to 150.0.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHubmozilla/firefoxpkg:github/mozilla/firefoxOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and included in Mozilla Firefox version 150.0.3. Users and administrators should update affected Firefox installations to version 150.0.3 or later to remediate this vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Description
JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 150.0.3.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2036983 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-45/ (opens in a new tab)
- github.com/crixpwn/CVE-2026-8389 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-8389 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2476466 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8389.json (opens in a new tab)