SEPTEMBER 8, 2026
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Case File

CVE-2026-63802

HIGH · CVSS 7.8 EPSS 0.14%

Source: NVD + CISA KEV + EPSS · Published 2026-07-19 · Last synced 2026-08-18

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's block cgroup (blk-cgroup) subsystem, where a use-after-free condition can occur due to concurrent releases of block group structures (blkgs). This flaw can lead to potential system crashes or arbitrary code execution, posing a significant risk to system stability and security. Organizations using Linux-based systems, particularly those relying on block cgroup functionality, should prioritize patching this vulnerability to mitigate the associated risks.

CVE
CVE-2026-63802
Severity
HIGH
CVSS
7.8
EPSS
0.14%
Linux

Original NVD 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.

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