MEDIUM
CVE-2021-24031
CWE-277Published: March 4, 2021· Updated: Jun 17, 2026
5.5
CVSS v3.1
Official 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.
Technical Analysis
CVE-2021-24031 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 5.5.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Affected Vendors & Products
facebook1 product(s)
zstandard
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (6)
→
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=981404Exploit · Issue Tracking · Mailing List · Third Party Advisory
→
https://github.com/facebook/zstd/issues/1630Exploit · Issue Tracking · Third Party Advisory
→
https://www.facebook.com/security/advisories/cve-2021-24031Vendor Advisory
→
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=981404Exploit · Issue Tracking · Mailing List · Third Party Advisory
→
https://github.com/facebook/zstd/issues/1630Exploit · Issue Tracking · Third Party Advisory
→
https://www.facebook.com/security/advisories/cve-2021-24031Vendor Advisory
Quick Facts
CVE IDCVE-2021-24031
CVSS Score5.5 / 10
SeverityMEDIUM
WeaknessCWE-277
CISA KEVNo
Affected1 vendor(s)
PublishedMar 4, 2021
Related CVEs (CWE-277)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-24031 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.