CVE-2026-90869— Pre-Authentication SSH Denial of Service via Malformed Public-Key Signature in Progress WS_FTP Server

Quick assessment

Affected

Progress Software WS_FTP Server

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

若攻击者知晓有效账户已注册的 SSH 公钥，则可在 Windows 系统上终止 Progress Software WS_FTP Server 2024.0.7 和 2025.0.4 之前版本中运行的共享 SSH 服务。

CVSS 7.5 · High Updated Oct 30, 2026

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

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Vulnerability Information

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Vulnerability Title

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

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

跨界内存读

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
Progress Software	WS_FTP Server	0 ~ 2024.0.7	-

II. Public POCs for CVE-2026-90869

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-90869

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Other References for CVE-2026-90869 (1)

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

https://www.cve.org/CVERecord?id=CVE-2026-90869

Same Patch Batch · Progress Software · 2026-10-29 · 15 CVEs total

CVE-2026-84295	10.0 CRITICAL	Improper Authentication in Progress WS_FTP Server
CVE-2026-90868	9.9 CRITICAL	OS Command Injection in Progress WS_FTP Server
CVE-2026-90863	9.1 CRITICAL	Privilege Escalation via Missing Authorization in WS_FTP Manager
CVE-2026-90864	9.1 CRITICAL	Host Administrator Path Containment Bypass in Progress WS_FTP Server
CVE-2026-90866	9.1 CRITICAL	Virtual Folder Path Confinement Bypass in Progress WS_FTP Server
CVE-2026-90865	9.0 CRITICAL	Command Injection via FTP Notification Variables in Progress WS_FTP Server
CVE-2026-90867	8.1 HIGH	Improper Access Control of Web Admin Console in Progress WS_FTP Server
CVE-2026-84294	7.7 HIGH	Information Disclosure in Ad Hoc Transfer in Progress WS_FTP Server
CVE-2026-84296	6.8 MEDIUM	SSH Multi-Factor Authentication Bypass in Progress WS_FTP Server
CVE-2026-90872	6.6 MEDIUM	Server-Side Script Injection in Manager Web UI in Progress WS_FTP Server
CVE-2026-90861	6.6 MEDIUM	Password Disclosure via Activity Logs Enabling Administrator Privilege Escalation in WS_FT
CVE-2026-90870	5.3 MEDIUM	Unauthenticated Ad Hoc Transfer Resource Exhaustion in Progress WS_FTP Server
CVE-2026-90871	5.3 MEDIUM	Path Traversal Leading to File Deletion in Ad Hoc Transfer and Web Transfer in Progress WS
CVE-2026-90862	4.3 MEDIUM	Web Transfer Module Multi-Factor Authentication Bypass in Progress WS_FTP Server

IV. Related Vulnerabilities

Same product: WS_FTP Server

Same vendor: Progress Software

Same weakness: CWE-125