What is CVE-2026-90866?

CVE-2026-90866 is a critical-severity vulnerability in Progress Software Ws FTP Server, classified under Path Traversal. CVSS score: 9.1/10. Published 2026-10-29.

How severe is CVE-2026-90866?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Path Traversal in Progress Software Ws FTP Server

CVE-2026-90866

A path traversal vulnerability in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows could allow a delegated Host Administrator to access locations outside their authorized scope, potentially enabling remote code execution.

Vulnerability class: Path Traversal (Directory Traversal)

Published 2026-10-29 · last modified 2026-10-29.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Progress Software Ws FTP Server

Weakness classification (CWE)

References

progress.lightning.force.com/lightning/r/Knowledge__kav/ka7Pb000001vl86IAA/view (vendor-advisory)

Frequently asked questions

What is CVE-2026-90866?: CVE-2026-90866 is a critical-severity vulnerability in Progress Software Ws FTP Server, classified under Path Traversal. CVSS score: 9.1/10. Published 2026-10-29.
How severe is CVE-2026-90866?: Critical severity. CVSS v3 base score is 9.1 out of 10.