CVE-2021-27203: In Dekart Private Disk 2.15, invalid use of the Type3 user buffer for IOCTL codes using METHOD_NEITHER results

Routine

MEDIUM 5.5DOWNGRADE

CVE-2021-27203 is a medium-severity flaw (CVSS 5.5) affecting private disk. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Dekart Private Disk 2.15, invalid use of the Type3 user buffer for IOCTL codes using METHOD_NEITHER results in arbitrary memory dereferencing.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-476
Published	2021-02-16
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: dekart

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

Am I affected?

Timeline

2021-02-16 20:15 UTCPublished CVE record published
2026-06-17 03:44 UTCUpdated Record last modified

dekart private disk DOWNGRADE

Affected: 2.15

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.15

1. Check installed version

apt-cache policy private-disk || rpm -q private-disk || private-disk --version

2. No fixed release: DOWNGRADE to a release before 2.15 (Debian / Ubuntu)

apt-cache madison private-disk sudo apt install private-disk=<VERSION_BEFORE_2.15> sudo apt-mark hold private-disk

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

dnf --showduplicates list private-disk sudo dnf downgrade private-disk-<VERSION_BEFORE_2.15> sudo dnf versionlock add private-disk

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-2021-27203?

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

Is CVE-2021-27203 being exploited?

CVE-2021-27203 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-2021-27203 affect?

CVE-2021-27203 affects private disk. Severity is medium (CVSS 5.5). In Dekart Private Disk 2.15, invalid use of the Type3 user buffer for IOCTL codes using METHOD_NEITHER results in arbitrary memory dereferencing.

How urgent is CVE-2021-27203?

Priority 32/100. Public exploit reference

References

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