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NVD / CVE Program· CNA Linux

CVE-2026-64112: rbd: eliminate a race in lock_dwork draining on unmap

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.10% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 3427d7ae38337066ce88b68302e285d344ab756b, 9400efc76b42c751211974a25c91d2c19c65b01b, 9dcd4f5c99b491c37be90b0bd9988db48225fb75; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 3427d7ae38337066ce88b68302e285d344ab756b, 9400efc76b42c751211974a25c91d2c19c65b01b, 9dcd4f5c99b491c37be90b0bd9988db48225fb75; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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().

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 0th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.12 and later · before 6.12.92
  • linux linux kernel6.13 and later · before 6.18.34
  • linux linux kernel6.19 and later · before 7.0.11
  • linux linux kernel7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.12affected
    • fd22aef8b47cfc068448df65c1183698b0abd815 and later · before 3427d7ae38337066ce88b68302e285d344ab756baffected · git
    • fd22aef8b47cfc068448df65c1183698b0abd815 and later · before 9dcd4f5c99b491c37be90b0bd9988db48225fb75affected · git
    • fd22aef8b47cfc068448df65c1183698b0abd815 and later · before 9400efc76b42c751211974a25c91d2c19c65b01baffected · git
    • fd22aef8b47cfc068448df65c1183698b0abd815 and later · before 9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90affected · git
    • before 4.12not affected · semver
    • 6.12.92 and later · up to and including 6.12.*not affected · semver
    • 6.18.34 and later · up to and including 6.18.*not affected · semver
    • 7.0.11 and later · up to and including 7.0.*not affected · semver
    • 7.1 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.12-17.0.12-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-64106Jul 19, 2026 · KVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits
    36Monitor
  • ← EarlierCVE-2026-64109Jul 19, 2026 · af_unix: Fix UAF read of tail->len in unix_stream_data_wait()
    35Monitor
  • Later →CVE-2026-64113Jul 19, 2026 · ixgbevf: fix use-after-free in VEPA multicast source pruning
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3427d7ae38337066ce88b68302e285d344ab756bVendor (CNA)
Linux Linux9400efc76b42c751211974a25c91d2c19c65b01bVendor (CNA)
Linux Linux9dcd4f5c99b491c37be90b0bd9988db48225fb75Vendor (CNA)
Linux Linux9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90Vendor (CNA)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.94-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-38352362 days apartposix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()KEV
    61This week
  • CVE-2026-640910 days apartbatman-adv: tt: fix TOCTOU race for reported vlans
    39Monitor
  • CVE-2026-640340 days apartnet: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer
    37Monitor
  • CVE-2026-5314524 days apartdrm/gem: Try to fix change_handle ioctl, attempt 4
    31Monitor
  • CVE-2026-5325024 days apartxsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata()
    31Monitor
  • CVE-2026-4343372 days apartrust_binder: avoid reading the written value in offsets array
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records