low advisory November 9, 2026

Progress Software WS_FTP Server: Denial of service via insufficient resource limits (CVE-2026-115339)

An unauthenticated remote attacker can trigger a denial of service condition in Progress Software WS_FTP Server versions prior to 2025.0.5 by exploiting insufficient resource limits.

Triage facts

Revision 1

Applicability: WS_FTP Server (< 2025.0.5)
Evidence: Unknown
Severity: Low
Action: Elevated
Sources: 1 public source
Freshness: Revision 1Nov 9, 21:59 UTC
Vulnerabilities: 1 CVE
Source quality: A1Roughly even chance

Progress Software WS_FTP Server versions prior to 2025.0.5 contain a vulnerability regarding insufficient resource limits. This flaw allows an unauthenticated remote attacker to cause a denial of service (DoS) on affected Windows-based systems. As of this report, the specific mechanics of the resource exhaustion (e.g., connection flooding or memory exhaustion) have not been detailed by the vendor or NVD.

Impact

Successful exploitation results in a denial of service, rendering the WS_FTP service unresponsive to legitimate users.

Recommendation

Patch affected systems by upgrading to WS_FTP Server version 2025.0.5 or later.
Audit internet-facing WS_FTP Server instances to ensure they are not accessible to unauthorized networks until patching is completed.
Monitor service logs for an anomalous spikes in connection requests or sudden service termination events that may indicate exploitation attempts.

Immediate actions

Upgrade Progress Software WS_FTP Server to version 2025.0.5 or later

IT Operations 48h

Threat Hunt

Identify sudden service instability or crashes in WS_FTP Server

T1499 medium medium confidence monitor or close

Data: Windows System Event Logs (Service Control Manager), WS_FTP Application Logs

Mitigations

Restrict access to WS_FTP Server to known, trusted IP addresses

immediate SOC

CVE-2026-115339