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TI-2026-47514 Aliases CVE-2026-67191GHSA-2w83-j663-7qg5

Xlight FTP Server < 3.9.5 Pre-Auth Heap Buffer Overflow via SSH Parser

Priority MEDIUM 44CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-122 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00963 61st percentileScored 2026-11-07
Fix Fixed Xlight FTP Server (Xlight): 3.9.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
XlightXlight FTP Serverbefore 3.9.53.9.5Patch availableCNA
  • Xlight FTP Server VendorXlight Affected before 3.9.5 Fixed in 3.9.5 Patch available CNA

Remediation

  • Fix · CNA Xlight FTP Server (Xlight) Fixed in 3.9.5

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Xlight FTP Server 3.9.5

    3 records Highest priority Priority MEDIUM 2 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-47515 Xlight FTP Server < 3.9.5 Pre-Auth Stack Buffer Overflow via SSH GCM CipherPriority MEDIUM 44
    • TI-2026-47516 Xlight FTP Server < 3.9.5 Information Disclosure via USER CommandPriority LOW 37
    Show all 3 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-67191
  2. 2026-10-03 Alias added: GHSA-2w83-j663-7qg5

References

Other 1

  • TI-2026-47515 Xlight FTP Server < 3.9.5 Pre-Auth Stack Buffer Overflow via SSH GCM Cipher CVSS 4.0CRITICAL 9.2
  • TI-2026-47516 Xlight FTP Server < 3.9.5 Information Disclosure via USER Command CVSS 4.0MEDIUM 6.9

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences