CVE-2026-66154 Security feature bypass in GMS
Insufficient certificate validation in SonicWall GMS allows attackers to perform unauthorized changes via Man-in-the-Middle attacks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66154?
CVE-2026-66154 is a high-severity vulnerability in SonicWall GMS, published on 11 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An insufficient certificate validation in a privileged communication workflow, was identified in a GMS application 9.5.1 (Build 9510.1044) and earlier versions which, under a successful MitM attack and controlled network conditions, could permit unauthorized changes.
Weakness: CWE-295
Which versions are affected by CVE-2026-66154?
How do I fix CVE-2026-66154?
No fix has been published for CVE-2026-66154 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-66154 being exploited?
There is no known exploitation of CVE-2026-66154 in the wild and no public exploit code.
Sources
Also known as GHSA-5h7r-wrwv-5rj5.