Security readout for executives and security teams
Plain-English summary
This Linux btrfs flaw can hang a system workload when storage metadata space is exhausted in a specific allocation path. The known impact is denial of service, not data theft or code execution. It matters most where Linux hosts use btrfs and may run close to full.
Executive priority
Treat this as a reliability risk for affected Linux storage hosts. It is not evidenced as exploited in the wild, but a deadlock can disrupt services. Patch during normal vulnerability maintenance, escalating priority for critical btrfs-backed systems.
Technical view
CVE-2021-38203 affects btrfs in Linux kernels before 5.13.4. Processes can trigger allocation of new system chunks while system space_info has insufficient free space, causing a deadlock. The public bundle points to the Linux 5.13.4 changelog and a kernel commit as the fix context.
Likely exposure
Exposure appears limited to Linux systems using btrfs on kernels before 5.13.4, or vendor kernels lacking the referenced fix. NetApp published an advisory, but this bundle does not provide exact affected NetApp product versions.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not listed as KEV. The described trigger requires processes on an affected btrfs system to create the low-space allocation condition that leads to deadlock.
Researcher notes
The bundle lacks CVSS, CWE, and precise downstream product version details. Analysis should stay anchored to upstream btrfs before 5.13.4 and the referenced commit. Avoid claiming remote exploitability, privilege requirements, or data compromise from these sources alone.
Mitigation direction
- Upgrade to Linux kernel 5.13.4 or a vendor kernel containing the referenced btrfs fix.
- Check NetApp advisory NTAP-20210902-0010 for platform-specific status and guidance.
- Prioritize btrfs hosts that may run low on metadata or system allocation space.
- Monitor vendor advisories if using downstream or appliance-maintained Linux kernels.
Validation and detection
- Inventory Linux hosts and identify which filesystems are mounted as btrfs.
- Confirm kernel versions are 5.13.4 or include the referenced upstream commit.
- Review storage telemetry for btrfs volumes operating near capacity.
- Check NetApp-managed environments against the published NetApp advisory.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-38203 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4CVE reference · x_refsource_MISC
- https://github.com/torvalds/linux/commit/1cb3db1cf383a3c7dbda1aa0ce748b0958759947CVE reference · x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210902-0010/CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.