CVE-2021-4197An unprivileged write to the file handler flaw in the Linux kernel's control groups and namespaces subsystem was found in the way users…
- 7.8HighCVSS base score
- 0.54%Exploitation in 30 daysEPSS · top 54% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
An unprivileged write to the file handler flaw in the Linux kernel's control groups and namespaces subsystem was found in the way users have access to some less privileged process that are controlled by cgroups and have higher privileged parent process. It is actually both for cgroup2 and cgroup1 versions of control groups. A local user could use this flaw to crash the system or escalate their privileges on the system.
Timeline
ID reserved
By redhat
- 3 months later
· 3 months later
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.54% · top 54% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
kernel
- affected Linux kernel 5.17-rc1
References
References6
- https://bugzilla.redhat.com/show_bug.cgi?id=2035652 (opens in a new tab)x_refsource_MISCx_transferred
- https://lore.kernel.org/lkml/20211209214707.805617-1-tj%40kernel.org/T/ (opens in a new tab)x_refsource_MISCx_transferred
- DSA-5127 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- DSA-5173 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- https://www.oracle.com/security-alerts/cpujul2022.html (opens in a new tab)x_refsource_MISCx_transferred
- https://security.netapp.com/advisory/ntap-20220602-0006/ (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-34056 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-4197)Record last updated .