How severe is CVE-2026-86134?

CVE-2026-86134 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-86134 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-86134?

CVE-2026-86134 affects Watchguard Fireware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-86134?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-86134 published?

CVE-2026-86134 was published on 2026-09-30 and last updated on 2026-10-06.

CVE-2026-86134

CVE-2026-86134 is a high-severity vulnerability in Watchguard Fireware with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Watchguard Fireware
Published: 2026-09-30
Last modified: 2026-10-06

Description

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.

Frequently asked questions

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.
How severe is CVE-2026-86134?: CVE-2026-86134 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-86134 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-86134?: CVE-2026-86134 affects Watchguard Fireware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-86134?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-86134 published?: CVE-2026-86134 was published on 2026-09-30 and last updated on 2026-10-06.

References

https://psirt.watchguard.com/CVE-2026-86134

Affected products (1)

cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:*

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