🛡️ CVE-2026-67191

🔴 CVSS 9.8 — Critical ✅ No Known Exploit CWE-122 NVD
9.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2026-67191 is classified as CWE-122: Heap-based Buffer Overflow. A write past the end of a heap allocation corrupts allocator metadata or neighbouring objects.

Affected software

CVE-2026-67191 is recorded against 1 package.

  • unknown

Timeline and source

Published on 29 July 2026 and last revised on 30 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

www.vulncheck.com
www.xlightftpd.com

Details

Severity CRITICAL
CVSS Score 9.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-122
Public Exploit ✅ No
Source NVD
Published 2026-07-29
Updated 2026-08-11
Modified 2026-07-30
Fix URL N/A

Affected Packages

Software From version Fixed in
unknown — —

Similar Threats

Exploit Protection

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CVE-2026-67191 carries CVSS 9.8 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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