CVE-2026-90869 PUBLISHED

Pre-Authentication SSH Denial of Service via Malformed Public-Key Signature in Progress WS_FTP Server

Assigner: ProgressSoftware
Reserved: 14.09.2026 Published: 29.10.2026 Updated: 29.10.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Progress Software
Product	WS_FTP Server
Versions	Default: unaffected affected from 0 to 2024.0.7 (excl.) affected from 0 to 2025.0.4 (excl.)

Workarounds

Restrict network access to the SSH/SFTP service to trusted clients and disable SSH/SFTP access if it is not required. Contact Progress Software Technical Support for guidance on available mitigations.

Credits

Niv Levy (restricted) finder

References

https://progress.lightning.force.com/lightning/r/Knowledge__kav/ka7Pb000001vl86IAA/view

Problem Types

CWE-125: Out-of-bounds Read CWE
CWE-20: Improper Input Validation CWE

Impacts

Overread Buffers - Improper handling of input data could result in denial of service.