blk-cgroup: fix leaks and online flag on radix_tree_insert failure
Key facts
- Attack vector
- —
- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 6 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix leaks and online flag on radix_tree_insert failure When radix_tree_insert() fails in blkg_create(), the error path has two issues: 1. blkg->online is set to true unconditionally, even when the blkg was never fully inserted. Move the assignment inside the success block. 2. The error path calls blkg_put() without first calling percpu_ref_kill(). Because the refcount is still in percpu mode, percpu_ref_put() only does this_cpu_sub() without checking for zero, so blkg_release() is never triggered. This permanently leaks the blkg memory, its percpu iostat, policy data, the parent blkg reference, and the cgroup css reference — the latter preventing the cgroup from ever being destroyed. Fix by replacing blkg_put() with percpu_ref_kill(), matching the pattern used in blkg_destroy().
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-93795
- 2026-10-03 Alias added: GHSA-q3xm-frv6-mwqx
- 2026-10-03 Fix available: Linux/Linux@0f840db042caee9d2f3dcdcf97d6674f6e4c1e30, Linux/[email protected], Linux/[email protected] +5 · CNA
- 2026-10-03 4 new references · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 7
- https://git.kernel.org/stable/c/0f840db042caee9d2f3dcdcf97d6674f6e4c1e30
- https://git.kernel.org/stable/c/f53945d7c712efe63fadbcc5ffed6370871fd0d3
- https://git.kernel.org/stable/c/ada8270ccdb6f212da5eb22614c28ea418746a4a
- https://git.kernel.org/stable/c/c3650be82ef6e7af13b79b2d10a7363bdf54aa7f
- https://git.kernel.org/stable/c/6e85f02d45b5977c0326a8d854c6db878aa6b34a
- https://git.kernel.org/stable/c/4c0d150fb98ea40760611979f4e664c244b20966
- https://git.kernel.org/stable/c/dbbca20764382b4d411ec2918f4e278ffe547acc
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Sources
- CVE-2026-93795 · CVE Program
- CVE-2026-93795 · NVD
- FIRST EPSS
- GHSA-q3xm-frv6-mwqx · GitHub Advisory Database · CC BY 4.0
- CVE-2026-93795 · Red Hat security data · CC BY 4.0
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