CVE-2020-28864: Buffer overflow in WinSCP 5.17.8 allows a malicious FTP server to cause a denial of service or possibly have o

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2020-28864 is a critical-severity flaw (CVSS 9.8) affecting winscp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in WinSCP 5.17.8 allows a malicious FTP server to cause a denial of service or possibly have other unspecified impact via a long file name.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.8% (top 13%)
CISA exploited list	No
Weakness	CWE-120
Published	2020-11-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: winscp

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-11-23 19:15 UTCPublished CVE record published
2026-06-17 03:10 UTCUpdated Record last modified

winscp winscp DOWNGRADE

Affected: 5.17.8

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.17.8

1. Check installed version

apt-cache policy winscp || rpm -q winscp || winscp --version

2. No fixed release: DOWNGRADE to a release before 5.17.8 (Debian / Ubuntu)

apt-cache madison winscp sudo apt install winscp=<VERSION_BEFORE_5.17.8> sudo apt-mark hold winscp

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list winscp sudo dnf downgrade winscp-<VERSION_BEFORE_5.17.8> sudo dnf versionlock add winscp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-28864?

winscp: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-28864 being exploited?

CVE-2020-28864 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-28864 affect?

CVE-2020-28864 affects winscp. Severity is critical (CVSS 9.8). Buffer overflow in WinSCP 5.17.8 allows a malicious FTP server to cause a denial of service or possibly have other unspecified impact via a long file name.

How urgent is CVE-2020-28864?

Priority 61/100. Critical severity; Remotely exploitable, no login, no user action

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References

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