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CVE-2026-34909

Critical CVSS 10 Known exploited

Published 2026-05-22 · last changed 2026-07-23 · added to CISA KEV 2026-06-23

This one is being exploited in the wild.

CISA added CVE-2026-34909 to the Known Exploited Vulnerabilities catalog on 2026-06-23. Federal agencies are required to remediate it on a deadline. If you have affected machines, this is the class of finding that moves ahead of the rest of the queue.

The fix

We hold no Microsoft remediation data for CVE-2026-34909, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to access files on the underlying system that could be manipulated to access an underlying account.

Sources

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H