VulnerabilityPublished 25 Jul 2026Updated 6 Nov 2026

CVE-2026-64326: Linux kernel · block: skip sync_blockdev() on surprise removal in bdev_mark_dead()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in f41cf35ee2a1e31374b3f54e7579c55153506e70 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 17:04 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in f41cf35ee2a1e31374b3f54e7579c55153506e70, d6998ddd507c81e3829489a6ead23f17f5acb7fe, aa4c4a9315764b2b7a7182e72cc5ea87520436b4 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ d8530de5a6e82be0ce17a5fdf727a394bcf6444c, < f41cf35ee2a1e31374b3f54e7579c55153506e70	Fixed in f41cf35ee2a1e31374b3f54e7579c55153506e70
LinuxLinux	Affected ≥ d8530de5a6e82be0ce17a5fdf727a394bcf6444c, < d6998ddd507c81e3829489a6ead23f17f5acb7fe	Fixed in d6998ddd507c81e3829489a6ead23f17f5acb7fe
LinuxLinux	Affected ≥ d8530de5a6e82be0ce17a5fdf727a394bcf6444c, < aa4c4a9315764b2b7a7182e72cc5ea87520436b4	Fixed in aa4c4a9315764b2b7a7182e72cc5ea87520436b4
LinuxLinux	Affected ≥ d8530de5a6e82be0ce17a5fdf727a394bcf6444c, < 9818bcae3c0ca1dde4b9a334125c46676e0a9b29	Fixed in 9818bcae3c0ca1dde4b9a334125c46676e0a9b29
LinuxLinux	Affected ≥ d8530de5a6e82be0ce17a5fdf727a394bcf6444c, < 49f06cff50a4ccf3b7a1a662ceb892b3b21a527a	Fixed in 49f06cff50a4ccf3b7a1a662ceb892b3b21a527a
LinuxLinux	Affected =6.6	Fixed in–

Description

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).

References

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