Quick answers
- Is CVE-2026-86133 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-86133 being exploited in the wild.
- How severe is CVE-2026-86133?
- Informational severity, published 30 September 2026.
- Which products and versions are affected?
- Watchguard Fireware OS Default: >=2026.3 <2026.3.2, >=2025.0 <2026.2.3, >=12.0 <12.12.3; T15/T35: >=12.0 <12.5.21.
- Is there a fix for CVE-2026-86133?
- A patch was published on 2026-09-29: Fireware OS 2026.3.2, 2026.2.3, 12.12.3, 12.5.21 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-86133 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-86133?
- Check whether you run Watchguard Fireware OS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an integer underflow (CWE-191) in the iked daemon occurring after successful IKEv2 handshake completion. An authenticated attacker on the network can send a specially crafted encrypted IKEv2 message to trigger the underflow, causing the daemon process to crash. The flaw is reachable over the network after authentication is established, with patches available in Fireware OS versions 2026.3.2, 2026.2.3, 12.12.3, and 12.5.21.
Affected products
- WatchGuard Fireware OS Default: >=2026.3 <2026.3.2, >=2025.0 <2026.2.3, >=12.0 <12.12.3; T15/T35: >=12.0 <12.5.21
Timeline
- 2026-09-29: disclosed
- 2026-09-29: patched: Fireware OS 2026.3.2, 2026.2.3, 12.12.3, 12.5.21