CVE-2021-24031

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-03-04 · updated 2026-06-17
Weakness: CWE-277

Description

In the Zstandard command-line utility prior to v1.4.1, output files were created with default permissions. Correct file permissions (matching the input) would only be set at completion time. Output files could therefore be readable or writable to unintended parties.

Affected products

Facebook Zstandard: before 1.4.1 — fixed in 1.4.1

How to fix

Upgrade to a fixed version: Facebook Zstandard 1.4.1. Check the vendor advisory for mitigations.

References

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=981404
https://github.com/facebook/zstd/issues/1630
https://www.facebook.com/security/advisories/cve-2021-24031
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=981404
https://github.com/facebook/zstd/issues/1630
https://www.facebook.com/security/advisories/cve-2021-24031

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