CVE-2026-67193: Xlight FTP Server < 3.9.5 Information Disclosure via USER Command

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-29 · updated 2026-10-23
Weakness: CWE-203

Description

Xlight FTP Server before 3.9.5 contains an information disclosure vulnerability that allows unauthenticated attackers to obtain the server's current GetTickCount() value by sending a USER command with a username ending in the :adm suffix. Attackers can trigger the admin protocol path within the standard FTP listener pre-authentication to leak timing information from the FTP 331 response without requiring a separate port or configuration change.

Affected products

Xlight FTP Server: before 3.9.5 — fixed in 3.9.5

How to fix

Upgrade to a fixed version: Xlight FTP Server 3.9.5. Check the vendor advisory for mitigations.

References

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