CVE-2026-64326
What it is
In the Linux kernel, the following vulnerability has been resolved: block: skip sync_blockdev() on surprise removal in bdev_mark_dead() bdev_mark_dead()'s @surprise == true means the device is already gone. The filesystem callback fs_bdev_mark_dead() honours this and skips sync_filesystem(), but the bare block device path (no ->mark_dead op) lost its !surprise guard when the holder ->mark_dead callback was wired up (see Fixes), and now calls sync_blockdev() unconditionally, which can hang forever waiting on writeback that can no longer complete. syzkaller hit this via nvme_reset_work()'s "I/O queues lost" path: nvme_mark_namespaces_dead() -> blk_mark_disk_dead() -> bdev_mark_dead(bdev, true) -> sync_blockdev() blocks in folio_wait_writeback(), wedging the reset worker and every task waiting on it. Skip the sync on surprise removal, matching fs_bdev_mark_dead(); invalidate_bdev() still runs. Orderly removal (surprise == false) is unchanged. Found by FuzzNvme(Syzkaller with FEMU fuzzing framework).
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 5.5 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Analyzed
Affected
- Linux Kernel < 6.6.145
- Linux Kernel < 6.12.96
- Linux Kernel < 6.18.39
- Linux Kernel < 7.1.4
Attack profile CVSS 3.1 · 5.5
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-64326.md and follow it. Check whether this project is affected by CVE-2026-64326. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a
- https://git.kernel.org/stable/c/9818bcae3c0ca1dde4b9a334125c46676e0a9b29
- https://git.kernel.org/stable/c/aa4c4a9315764b2b7a7182e72cc5ea87520436b4
- https://git.kernel.org/stable/c/d6998ddd507c81e3829489a6ead23f17f5acb7fe
- https://git.kernel.org/stable/c/f41cf35ee2a1e31374b3f54e7579c55153506e70
References
- https://git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a
- https://git.kernel.org/stable/c/9818bcae3c0ca1dde4b9a334125c46676e0a9b29
- https://git.kernel.org/stable/c/aa4c4a9315764b2b7a7182e72cc5ea87520436b4
- https://git.kernel.org/stable/c/d6998ddd507c81e3829489a6ead23f17f5acb7fe
- https://git.kernel.org/stable/c/f41cf35ee2a1e31374b3f54e7579c55153506e70