Quick answers
- Is CVE-2026-77540 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-77540 being exploited in the wild.
- How severe is CVE-2026-77540?
- Critical severity, with a CVSS score of 9.1, published 26 August 2026.
- Which products and versions are affected?
- Ubiquiti UniFi OS.
- Is there a fix for CVE-2026-77540?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-77540 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-77540?
- Check whether you run Ubiquiti UniFi OS. 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
An improper input validation vulnerability in UniFi OS Server allows command injection on the host device. The vulnerability requires the attacker to have network access and high privileges to exploit it. By sending crafted input that bypasses validation checks, an attacker can inject and execute arbitrary system commands with the privileges of the UniFi OS process. This could lead to complete system compromise, unauthorized access to network credentials, or lateral movement within the network infrastructure.
Affected products
- Ubiquiti UniFi OS
Timeline
- 2026-08-26: disclosed