CVE-2021-33983: Buffer Overflow vulnerability in Dvidelabs flatcc v.0.6.0 allows local attacker to execute arbitrary code via

Routine

HIGH 7.8DOWNGRADE

CVE-2021-33983 is a high-severity flaw (CVSS 7.8) affecting flatcc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer Overflow vulnerability in Dvidelabs flatcc v.0.6.0 allows local attacker to execute arbitrary code via the fltacc execution of the error_ref_sym function.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 76%)
CISA exploited list	No
Weakness	CWE-120
Published	2023-02-17
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: flatcc project

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

Am I affected?

Timeline

2023-02-17 18:15 UTCPublished CVE record published
2026-06-17 03:55 UTCUpdated Record last modified

flatcc project flatcc DOWNGRADE

Affected: 0.6.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.6.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.6.0 (Debian / Ubuntu)

apt-cache madison flatcc sudo apt install flatcc=<VERSION_BEFORE_0.6.0> sudo apt-mark hold flatcc

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

dnf --showduplicates list flatcc sudo dnf downgrade flatcc-<VERSION_BEFORE_0.6.0> sudo dnf versionlock add flatcc

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-2021-33983?

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

Is CVE-2021-33983 being exploited?

CVE-2021-33983 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-2021-33983 affect?

CVE-2021-33983 affects flatcc. Severity is high (CVSS 7.8). Buffer Overflow vulnerability in Dvidelabs flatcc v.0.6.0 allows local attacker to execute arbitrary code via the fltacc execution of the error_ref_sym function.

How urgent is CVE-2021-33983?

Priority 38/100. High severity; Public exploit reference

References

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