MEDIUM
CVE-2021-38203
CWE-667Published: August 8, 2021· Updated: Jun 17, 2026
5.5
CVSS v3.1
Official Description
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
Technical Analysis
CVE-2021-38203 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 availability disruption (denial of service), 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
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Vendors & Products
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
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Official Patches & Advisories
All References (6)
→
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4Mailing List · Patch · Vendor Advisory
→
https://github.com/torvalds/linux/commit/1cb3db1cf383a3c7dbda1aa0ce748b0958759947Exploit · Patch · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210902-0010/Third Party Advisory
→
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4Mailing List · Patch · Vendor Advisory
→
https://github.com/torvalds/linux/commit/1cb3db1cf383a3c7dbda1aa0ce748b0958759947Exploit · Patch · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210902-0010/Third Party Advisory
Quick Facts
CVE IDCVE-2021-38203
CVSS Score5.5 / 10
SeverityMEDIUM
WeaknessCWE-667
CISA KEVNo
Affected2 vendor(s)
PublishedAug 8, 2021
Related CVEs (CWE-667)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-38203 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. CVE data is provided under the NVD usage policy.