High severity · published Oct 29, 2026
CVE-2026-90869
Pre-Authentication SSH Denial of Service via Malformed Public-Key Signature in Progress WS_FTP Server
New
7.5
CVSS
–
EPSS
No
On KEV
Description
A remote attacker who knows a valid account's enrolled SSH public key can terminate the shared SSH service in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WS
WS_FTP Server · Progress Software
before 2024.0.7; before 2025.0.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-90869
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-90869
vendor-advisory
https://progress.lightning.force.com/lightning/r/Knowledge__kav/ka7Pb000001vl86IAA/view
More from WS_FTP Server
10.0
CVE-2026-84295
Improper Authentication in Progress WS_FTP Server
9.9
CVE-2026-90868
OS Command Injection in Progress WS_FTP Server
9.1
CVE-2026-90866
Virtual Folder Path Confinement Bypass in Progress WS_FTP Server
9.1
CVE-2026-90864
Host Administrator Path Containment Bypass in Progress WS_FTP Server
9.1
CVE-2026-90863
Privilege Escalation via Missing Authorization in WS_FTP Manager