# CVE-2026-77544: Ubiquiti UniFi Gateway out-of-bounds write denial of service

Source: https://junglewise.ai/threats/cve-2026-77544-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-2026-77544 · Severity: high · CVSS 7.5 · Published 2026-09-22

UniFi Gateway devices contain an out-of-bounds write vulnerability that allows a network-adjacent attacker to trigger a denial of service, rendering the gateway temporarily unavailable. An attacker with network access could crash or freeze the device, disrupting network connectivity for all users relying on it.

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

## Quick answers

**Is CVE-2026-77544 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77544 being exploited in the wild.

**How severe is CVE-2026-77544?** High severity, with a CVSS score of 7.5, published 22 September 2026.

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

**Is there a fix for CVE-2026-77544?** 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-2026-77544 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-77544?** Check whether you run Ubiquiti UniFi Gateway. 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 write vulnerability exists in UniFi Gateway firmware, exploitable via network access without authentication. Successful exploitation causes a denial of service by crashing or hanging the gateway process. The vulnerability requires the attacker to be on the same network or have adjacent network access to the device.

## Affected products

- Ubiquiti UniFi Gateway

## 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)
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- [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)