Vulnerability Description
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 Score
CRITICAL
Related Weaknesses (CWE)
References
- https://www.vulncheck.com/advisories/xlight-ftp-server-pre-auth-heap-buffer-over
- https://www.xlightftpd.com/whatsnew.htm
FAQ
What is CVE-2026-67191?
CVE-2026-67191 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 malform...
How severe is CVE-2026-67191?
CVE-2026-67191 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-67191?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.