CVE-2026-63802

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.

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/0ab5ee5a1badb58cbb2242617cb01a4972b1f2a2	Patch
https://git.kernel.org/stable/c/5e5b7f2ef854936e95dceb6a2fdfefcb7152d2c6	Patch
https://git.kernel.org/stable/c/96e545410c4f74c89d496c1d5d9ef8d08f14368b	Patch
https://git.kernel.org/stable/c/afebe44facc48a61761e885bbb7f0380d4a603ec	Patch
https://git.kernel.org/stable/c/bbebd9425cad3573d1527441753899b926525a0f	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:6.4:-::::::
	cpe:2.3:o:linux:linux_kernel:6.4:rc7::::::

History

19 Oct 2026, 20:19

Type	Values Removed	Values Added
CWE		CWE-362

Information

Published : 2026-07-19 12:16

Updated : 2026-10-19 20:19

NVD link : CVE-2026-63802

Mitre link : CVE-2026-63802

CVE.ORG link : CVE-2026-63802

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-416

Use After Free

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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