PT-2026-65836 · Xlight · Xlight Ftp Server

CVE-2026-67191 · Published 2026-07-29 · Updated 2026-07-29

NVD

CVSS v3.1

9.8

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Fix

Heap Based Buffer Overflow

Weakness Enumeration

CWE-122

Related Identifiers

CVE-2026-67191

Affected Products

Xlight Ftp Server

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-67191 · Security Note
• https://vulncheck.com/advisories/xlight-ftp-server-pre-auth-heap-buffer-overflow-via-ssh-parser · Note
• https://xlightftpd.com/whatsnew.htm · Note