CVE-2026-63802blk-cgroup: fix UAF in __blkcg_rstat_flush()
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Analyzed
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 20cb1c2fb7568a6054c55defe044311397e01ddb before 96e545410c4f74c89d496c1d5d9ef8d08f14368b; from 20cb1c2fb7568a6054c55defe044311397e01ddb before bbebd9425cad3573d1527441753899b926525a0f; 20cb1c2fb7568a6054c55defe044311397e01ddb builds before 5e5b7f2ef854936e95dceb6a2fdfefcb7152d2c6; from 20cb1c2fb7568a6054c55defe044311397e01ddb before afebe44facc48a61761e885bbb7f0380d4a603ec; 20cb1c2fb7568a6054c55defe044311397e01ddb builds before 0ab5ee5a1badb58cbb2242617cb01a4972b1f2a2; 0f6090d90f627d8c58f939067d6c6821ce1b3c68; from 6.3.9 before 6.4 | CNA record |
linux linux_kernel linux:linux_kernel | from 6.3.9 before 6.4; from 6.4.1 before 6.6.144; from 6.7 before 6.12.95; from 6.13 before 6.18.38; from 6.19 before 7.1.3; 6.4; 6.4 | NVD |
References
- https://git.kernel.org/stable/c/96e545410c4f74c89d496c1d5d9ef8d08f14368bpatch
- https://git.kernel.org/stable/c/bbebd9425cad3573d1527441753899b926525a0fpatch
- https://git.kernel.org/stable/c/5e5b7f2ef854936e95dceb6a2fdfefcb7152d2c6patch
- https://git.kernel.org/stable/c/afebe44facc48a61761e885bbb7f0380d4a603ecpatch
- https://git.kernel.org/stable/c/0ab5ee5a1badb58cbb2242617cb01a4972b1f2a2patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.