# CVE-2026-77558: Ubiquiti UniFi Gateway out-of-bounds read DoS

Source: https://junglewise.ai/threats/cve-2026-77558-a-malicious-actor-with-access-to-the-network-could-exploit-an-out  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-22. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-77558 · Severity: high · CVSS 7.5 · Published 2026-09-22

Ubiquiti UniFi Gateway devices are network appliances that manage connectivity and routing for businesses. An attacker on the network could exploit an out-of-bounds read vulnerability to crash the gateway, interrupting network service and affecting all devices it protects. This requires network access but no authentication.

Technologies: [Ubiquiti UniFi Gateway](https://junglewise.ai/threats/technologies/unifi-gateway). Vendors: [Ubiquiti](https://junglewise.ai/threats/vendors/ubiquiti).

## Quick answers

**Is CVE-2026-77558 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77558 being exploited in the wild.

**How severe is CVE-2026-77558?** High severity, with a CVSS score of 7.5, published 22 September 2026.

**Which products and versions are affected?** Ubiquiti UniFi Gateway certain versions.

**Is there a fix for CVE-2026-77558?** 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-2026-77558 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-77558?** Check whether you run Ubiquiti UniFi Gateway at an affected version. 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 out-of-bounds read vulnerability in UniFi Gateway devices allows a network-adjacent attacker to trigger a denial of service condition. The vulnerability is exploitable by a malicious actor with network access to the device, without requiring authentication or user interaction. Successful exploitation results in a crash or unavailability of the gateway.

## Affected products

- Ubiquiti UniFi Gateway certain versions

## Timeline

- 2026-09-22: disclosed

## References

- [https://community.ui.com/releases/Security-Advisory-Bulletin-069-069/07e367a7-edec-4d85-a058-f97e5ce9ac9c](https://community.ui.com/releases/Security-Advisory-Bulletin-069-069/07e367a7-edec-4d85-a058-f97e5ce9ac9c)

## Related threats

- [Ubiquiti UniFi gateway out-of-bounds write denial of service](https://junglewise.ai/threats/cve-2026-95862-a-malicious-actor-with-access-to-the-network-could-exploit-an-out)
- [Ubiquiti UniFi Gateway uncontrolled recursion denial of service](https://junglewise.ai/threats/cve-2026-95861-a-malicious-actor-with-access-to-the-network-could-exploit-an)
- [Ubiquiti UniFi gateway out-of-bounds read denial of service](https://junglewise.ai/threats/cve-2026-77556-a-malicious-actor-with-access-to-the-network-could-exploit-an-out)
- [Ubiquiti UniFi Gateway out-of-bounds write denial of service](https://junglewise.ai/threats/cve-2026-77555-a-malicious-actor-with-access-to-the-network-could-exploit-an-out)
- [Ubiquiti UniFi Gateway out-of-bounds write denial of service](https://junglewise.ai/threats/cve-2026-77544-a-malicious-actor-with-access-to-the-network-could-exploit-an-out)