CVE-2021-3331

Name: CVE-2021-3331
Creator: NVD / NIST
Published: 2021-01-27T21:15:16.84+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 7.41%

Last modified Jun 17, 2026

CVE-2021-3331 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. WinSCP before 5.17.10 allows remote attackers to execute arbitrary programs when the URL handler encounters a crafted URL that loads session settings. (For example, this is exploitable in a default installation in which WinSCP is the handler for sftp:// URLs.). EPSS estimates a 7.41% chance of exploitation in the next 30 days.

Description

WinSCP before 5.17.10 allows remote attackers to execute arbitrary programs when the URL handler encounters a crafted URL that loads session settings. (For example, this is exploitable in a default installation in which WinSCP is the handler for sftp:// URLs.)

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

7.41%

93.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Winscp	Winscp	< 5.17.10

References

https://github.com/winscp/winscp/commit/faa96e8144e6925a380f94a97aa382c9427f688dPatch, Third Party Advisory
https://winscp.net/eng/docs/history#5.17.10Release Notes, Vendor Advisory
https://winscp.net/eng/docs/rawsettingsVendor Advisory
https://winscp.net/tracker/1943Patch, Vendor Advisory
https://github.com/winscp/winscp/commit/faa96e8144e6925a380f94a97aa382c9427f688dPatch, Third Party Advisory
https://winscp.net/eng/docs/history#5.17.10Release Notes, Vendor Advisory
https://winscp.net/eng/docs/rawsettingsVendor Advisory
https://winscp.net/tracker/1943Patch, Vendor Advisory

Timeline

Published: Jan 27, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3331?

How severe is CVE-2021-3331?

CVE-2021-3331 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 7.41% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3331?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3331?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST