UniFi OS Server: Active Debug Code
CVE-2026-77545 is a critical-severity active debug code vulnerability in UniFi OS Server from Ubiquiti, with a CVSS 3.1 base score of 9.0 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. The record lists version 5.1.37 as the first without the flaw, so updating UniFi OS Server to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update UniFi OS Server to 5.1.37 or a later version.
- Update Cloud Keys to 5.1.31 or a later version.
- Update Network Video Recorders to 5.1.31 or a later version.
- Read the advisory on community.ui.com for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Ubiquiti | UniFi OS Server | before 5.1.37 | 5.1.37 |
| Ubiquiti | Cloud Keys | before 5.1.31 | 5.1.31 |
| Ubiquiti | Network Video Recorders | before 5.1.31 | 5.1.31 |
| Ubiquiti | Enterprise Network Video Recorders | before 5.1.31 | 5.1.31 |
| Ubiquiti | Enterprise Network Attached Storage | before 5.1.31 | 5.1.31 |
| Ubiquiti | Dream Machines | before 5.1.31 | 5.1.31 |
| Ubiquiti | Enterprise Firewall Core | before 5.1.31 | 5.1.31 |
| Ubiquiti | Dream Routers | before 5.1.31 | 5.1.31 |
| Ubiquiti | Enterprise Fortress Gateway | before 5.1.31 | 5.1.31 |
| Ubiquiti | Cloud Gateways | before 5.1.31 | 5.1.31 |
| Ubiquiti | Dream Wall | before 5.1.31 | 5.1.31 |
| Ubiquiti | Express 7 | before 5.1.31 | 5.1.31 |
| Ubiquiti | Network Attached Storage | before 5.1.32 | 5.1.32 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H. Scored by CNA.
Official description
A malicious actor with access to the network, low privileges and under certain conditions could exploit an Active Debug Code vulnerability found in certain devices running UniFi OS to escalate privileges within such UniFi OS devices or instances.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Active Debug Code
The product is released with debugging code still enabled or active.
How developers prevent this class of flaw
- Remove debug code before deploying the application.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in UniFi OS Server
- 10.0 Critical severity
- 9.0 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.9 Critical severity
- 9.9 Critical severity
Recent Active Debug Code vulnerabilities
- 7.5 High severity
- 7.0 High severity
- 7.8 High severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Spotted an error? Tell us.