What is CVE-2026-86134?
A NULL pointer dereference vulnerability in the WatchGuard Fireware OS authentication process allows a remote, unauthenticated attacker to crash the management daemon by sending a specially request to the login interface, resulting in a denial of service.
The record classifies CVE-2026-86134 under weakness class CWE-476. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 5 days ago.
Severity and exploitation probability
- CVSS v4.0 base score
- 8.7 — High (derived from score)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - EPSS (FIRST)
- 0.4% probability of exploitation in the next 30 days, higher than 34.2% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-09-30
Is CVE-2026-86134 being exploited?
No public exploitation evidence for CVE-2026-86134 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-09-30. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.
Affected products and versions
- WatchGuard: Fireware OS
How to fix CVE-2026-86134
No vendor patch reference has been recorded for CVE-2026-86134 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-2026-86134
1 tracked threat in the Threadlinqs corpus references CVE-2026-86134, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.