CVE-2026-67191: critical vulnerability in Xlight FTP Server
Xlight FTP Server < 3.9.5 Pre-Auth Heap Buffer Overflow via SSH Parser
Published · Updated
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.3epss 1.0%
Xlight FTP Server before 3.9.5 contains a pre-authentication heap buffer overflow vulnerability that allows remote unauthenticated attackers to write past the end of a heap buffer by sending a malformed SSH client identification string. A logic error in the recv loop's termination condition uses an incorrect OR operator where an AND operator is required, enabling exploitation on any SSH or SFTP connection before authentication occurs.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
Xlight · Xlight FTP ServerRelated CVEs — Xlight FTP Server
In the same product, most dangerous first.