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VulnerabilityPublished Updated

CVE-2026-64112: Linux kernel · Race Condition

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in 9400efc76b42c751211974a25c91d2c19c65b01b : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
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
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in 9400efc76b42c751211974a25c91d2c19c65b01b, 3427d7ae38337066ce88b68302e285d344ab756b, 9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90 +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 26 Oct 2026.

What to do

Upgrade Linux kernel to 9400efc76b42c751211974a25c91d2c19c65b01b, 3427d7ae38337066ce88b68302e285d344ab756b, 9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90 or 9dcd4f5c99b491c37be90b0bd9988db48225fb75.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ fd22aef8b47cfc068448df65c1183698b0abd815, < 9400efc76b42c751211974a25c91d2c19c65b01b
Fixed in
  • 9400efc76b42c751211974a25c91d2c19c65b01b
LinuxLinuxAffected
  • ≥ fd22aef8b47cfc068448df65c1183698b0abd815, < 3427d7ae38337066ce88b68302e285d344ab756b
Fixed in
  • 3427d7ae38337066ce88b68302e285d344ab756b
LinuxLinuxAffected
  • ≥ fd22aef8b47cfc068448df65c1183698b0abd815, < 9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90
Fixed in
  • 9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90
LinuxLinuxAffected
  • ≥ fd22aef8b47cfc068448df65c1183698b0abd815, < 9dcd4f5c99b491c37be90b0bd9988db48225fb75
Fixed in
  • 9dcd4f5c99b491c37be90b0bd9988db48225fb75
LinuxLinuxAffected
  • =4.12
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: rbd: eliminate a race in lock_dwork draining on unmap Given how rbd_lock_add_request() and rbd_img_exclusive_lock() are written, lock_dwork may be (re)queued more than it's actually needed: for example in case a new I/O request comes in while we are in the middle of rbd_acquire_lock() on behalf of another I/O request. This is expected and with rbd_release_lock() preemptively canceling lock_dwork is benign under normal operation. A more problematic example is maybe_kick_acquire(): if (have_requests || delayed_work_pending(&rbd_dev->lock_dwork)) { dout("%s rbd_dev %p kicking lock_dwork\n", __func__, rbd_dev); mod_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0); } It's not unrealistic for lock_dwork to get canceled right after delayed_work_pending() returns true and for mod_delayed_work() to requeue it right there anyway. This is a classic TOCTOU race. When it comes to unmapping the image, there is an implicit assumption of no self-initiated exclusive lock activity past the point of return from rbd_dev_image_unlock() which unlocks the lock if it happens to be held. This unlock is assumed to be final and lock_dwork (as well as all other exclusive lock tasks, really) isn't expected to get queued again. However, lock_dwork is canceled only in cancel_tasks_sync() (i.e. later in the unmap sequence) and on top of that the cancellation can get in effect nullified by maybe_kick_acquire(). This may result in rbd_acquire_lock() executing after rbd_dev_device_release() and rbd_dev_image_release() run and free and/or reset a bunch of things. One of the possible failure modes then is a violated rbd_assert(rbd_image_format_valid(rbd_dev->image_format)); in rbd_dev_header_info() which is called via rbd_dev_refresh() from rbd_post_acquire_action(). Redo exclusive lock task draining to provide saner semantics and try to meet the assumptions around rbd_dev_image_unlock().

References

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