Instituto Nacional de ciberseguridad. Sección Incibe
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CVE-2026-63802

Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
19/07/2026
Last modified:
20/07/2026

Description

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> blk-cgroup: fix UAF in __blkcg_rstat_flush()<br /> <br /> When multiple blkgs in the same blkcg are released concurrently,<br /> a use-after-free can occur. The race happens when one blkg&amp;#39;s<br /> __blkcg_rstat_flush() removes another blkg&amp;#39;s iostat entries via<br /> llist_del_all(). The second blkg sees an empty list and proceeds<br /> to free itself while the first is still iterating over its entries.<br /> <br /> Move the flush from __blkg_release() (RCU callback) to blkg_release()<br /> (before call_rcu). This ensures the RCU grace period waits for any<br /> concurrent flush&amp;#39;s rcu_read_lock() section to complete before freeing.

Impact

Vector 3.x
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.80 HIGH
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x
7.80
Severity 3.x
HIGH

References to Advisories, Solutions, and Tools