Dream Machines: Out-of-bounds Read
CVE-2026-77556 is a high-severity out-of-bounds read vulnerability in Dream Machines from Ubiquiti, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 5.1.31 as the first without the flaw, so updating Dream Machines to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.52% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Dream Machines to 5.1.31 or a later version.
- Update Enterprise Firewalls to 5.1.31 or a later version.
- Update Dream Routers to 5.1.31 or a later version.
- Read the advisory on community.ui.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Ubiquiti | Dream Machines | before 5.1.31 | 5.1.31 |
| Ubiquiti | Enterprise Firewalls | before 5.1.31 | 5.1.31 |
| Ubiquiti | Dream Routers | 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 | before 4.0.21 | 4.0.21 |
| Ubiquiti | Express 7 | before 5.1.31 | 5.1.31 |
| Ubiquiti | UniFi Gateways | before 5.1.26 | 5.1.26 |
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
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.
Official description
A malicious actor with access to the network could exploit an Out-of-bounds Read vulnerability found in certain UniFi gateway devices to execute a Denial of Service (DoS) attack on the device.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
References
Advisories
Other vulnerabilities in Dream Machines
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 10.0 Critical severity
Recent Out-of-bounds Read vulnerabilities
- 9.1 Critical severity
- 7.5 High severity
- 8.1 High severity
- 7.0 High severity
- 8.7 High severity
- 7.1 High severity
Spotted an error? Tell us.