CVE-2026-90326
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BaseFortify
Vulnerability report for CVE-2026-90326, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-17
Last updated on: 2026-09-18
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
blk-cgroup: fix race between policy activation and blkg destruction
When switching an IO scheduler on a block device, blkcg_activate_policy()
allocates blkg_policy_data (pd) for all blkgs attached to the queue.
However, blkcg_activate_policy() may race with concurrent blkcg deletion,
leading to use-after-free and memory leak issues.
The use-after-free occurs in the following race:
T1 (blkcg_activate_policy):
- Successfully allocates pd for blkg1 (loop0->queue, blkcgA)
- Fails to allocate pd for blkg2 (loop0->queue, blkcgB)
- Enters the enomem rollback path to release blkg1 resources
T2 (blkcg deletion):
- blkcgA is deleted concurrently
- blkg1 is freed via blkg_free_workfn()
- blkg1->pd is freed
T1 (continued):
- Rollback path accesses blkg1->pd->online after pd is freed
- Triggers use-after-free
In addition, blkg_free_workfn() frees pd before removing the blkg from
q->blkg_list. This allows blkcg_activate_policy() to allocate a new pd
for a blkg that is being destroyed, leaving the newly allocated pd
unreachable when the blkg is finally freed.
Fix these races by extending blkcg_mutex coverage to serialize
blkcg_activate_policy() rollback and blkg destruction, ensuring pd
lifecycle is synchronized with blkg list visibility.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Linux | Linux | 81c1188905f88b77743d1fdeeedfc8cb7b67787d |
| Linux | Linux | bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a |
| Linux | Linux | f1c006f1c6850c14040f8337753a63119bba39b9 |
| Linux | Linux | f1c006f1c6850c14040f8337753a63119bba39b9 |
| Linux | Linux | f1c006f1c6850c14040f8337753a63119bba39b9 |
| Linux | Linux | 6.1.16 |
| Linux | Linux | 6.2.3 |
| Linux | Linux | 6.3 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
