High severity7.8NVD Advisory· Published Jul 19, 2026· Updated Aug 17, 2026
CVE-2026-63802
CVE-2026-63802
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.
Affected products
19- osv-coords15 versionspkg:linux/kernelpkg:rpm/opensuse/dtb-aarch64&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-64kb&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-azure&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-default&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-default-base&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-docs&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-kvmsmall&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-obs-build&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-obs-qa&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-rt&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-source&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-source&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/kernel-syms&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/kernel-zfcpdump&distro=openSUSE%20Leap%2016.0
>= 6.4.0, < 6.6.144+ 14 more
- (no CPE)range: >= 6.4.0, < 6.6.144
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1.160000.2.19
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 7.1.4-1.1
- (no CPE)range: < 6.12.0-160000.37.1
- (no CPE)range: < 6.12.0-160000.37.1
Patches
Vulnerability mechanics
References
5- git.kernel.org/stable/c/0ab5ee5a1badb58cbb2242617cb01a4972b1f2a2nvdPatch
- git.kernel.org/stable/c/5e5b7f2ef854936e95dceb6a2fdfefcb7152d2c6nvdPatch
- git.kernel.org/stable/c/96e545410c4f74c89d496c1d5d9ef8d08f14368bnvdPatch
- git.kernel.org/stable/c/afebe44facc48a61761e885bbb7f0380d4a603ecnvdPatch
- git.kernel.org/stable/c/bbebd9425cad3573d1527441753899b926525a0fnvdPatch
News mentions
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