blk-cgroup: fix UAF in __blkcg_rstat_flush()
Summary
| CVE | CVE-2026-63802 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-19 12:16:52 UTC |
| Updated | 2026-07-20 15:16:47 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix UAF in __blkcg_rstat_flush() When multiple blkgs in the same blkcg are released concurrently, a use-after-free can occur. The race happens when one blkg's __blkcg_rstat_flush() removes another blkg's iostat entries via llist_del_all(). The second blkg sees an empty list and proceeds to free itself while the first is still iterating over its entries. Move the flush from __blkg_release() (RCU callback) to blkg_release() (before call_rcu). This ensures the RCU grace period waits for any concurrent flush's rcu_read_lock() section to complete before freeing. |
Risk And Classification
Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.001680000 probability, percentile 0.063820000 (date 2026-07-20)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 20cb1c2fb7568a6054c55defe044311397e01ddb 96e545410c4f74c89d496c1d5d9ef8d08f14368b git | Not specified |
| CNA | Linux | Linux | affected 20cb1c2fb7568a6054c55defe044311397e01ddb bbebd9425cad3573d1527441753899b926525a0f git | Not specified |
| CNA | Linux | Linux | affected 20cb1c2fb7568a6054c55defe044311397e01ddb 5e5b7f2ef854936e95dceb6a2fdfefcb7152d2c6 git | Not specified |
| CNA | Linux | Linux | affected 20cb1c2fb7568a6054c55defe044311397e01ddb afebe44facc48a61761e885bbb7f0380d4a603ec git | Not specified |
| CNA | Linux | Linux | affected 20cb1c2fb7568a6054c55defe044311397e01ddb 0ab5ee5a1badb58cbb2242617cb01a4972b1f2a2 git | Not specified |
| CNA | Linux | Linux | affected 0f6090d90f627d8c58f939067d6c6821ce1b3c68 git | Not specified |
| CNA | Linux | Linux | affected 6.3.9 6.4 semver | Not specified |
| CNA | Linux | Linux | affected 6.4 | Not specified |
| CNA | Linux | Linux | unaffected 6.4 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.144 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.95 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.38 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.3 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/96e545410c4f74c89d496c1d5d9ef8d08f14368b | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/afebe44facc48a61761e885bbb7f0380d4a603ec | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/bbebd9425cad3573d1527441753899b926525a0f | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/5e5b7f2ef854936e95dceb6a2fdfefcb7152d2c6 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/0ab5ee5a1badb58cbb2242617cb01a4972b1f2a2 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.