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CVE-2021-3331

Status: ModifiedCritical (9.8)—
Severity9.8Critical · CVSS 3.1
Exploitation probability7.70 %higher than 95% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

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.)

CVSS

Base score
9.8
Version
3.1
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
7.70 %
Percentile among all scored CVEs
95
Score date
10/24/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Winscp — Winscp

CWEs

References

Show 8 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-3331",
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          "version": "2.0.3",
          "timestamp": "2026-10-08T21:02:17.906285Z"
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  "weaknesses": [
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    },
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    }
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}