CVE-2026-77540 Command injection in UniFi OS Server
High-privilege network attackers can execute arbitrary commands on UniFi OS Server hosts via improper input validation.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-77540?
CVE-2026-77540 is a critical command injection vulnerability in Ubiquiti Inc UniFi OS Server, published on 26 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
A malicious actor with access to the network and high privileges could exploit an Improper Input Validation vulnerability found in UniFi OS Server to execute a Command Injection on the host device.
Weakness: CWE-20
Which versions are affected by CVE-2026-77540?
How do I fix CVE-2026-77540?
No fix has been published for CVE-2026-77540 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-77540 being exploited?
There is no known exploitation of CVE-2026-77540 in the wild and no public exploit code.
Sources
Also known as GHSA-w5vh-8c24-45f5.