Linux KernelOperating system · Linux

CVE-2026-31557

HIGH · 7.5 CVSS v3.1 Published 2026-04-24

Fix available

A fix is available. Upgrade to 5.16 / 5.18 or later.

See remediation →

84/100

Remediation priority · High

Remotely reachable No privileges Zero-click Patch available

Official description

NVD · unedited

In the Linux kernel, the following vulnerability has been resolved: nvmet: move async event work off nvmet-wq For target nvmet_ctrl_free() flushes ctrl->async_event_work. If nvmet_ctrl_free() runs on nvmet-wq, the flush re-enters workqueue completion for the same worker:- A. Async event work queued on nvmet-wq (prior to disconnect): nvmet_execute_async_event() queue_work(nvmet_wq, &ctrl->async_event_work) nvmet_add_async_event() queue_work(nvmet_wq, &ctrl->async_event_work) B. Full pre-work chain (RDMA CM path): nvmet_rdma_cm_handler() nvmet_rdma_queue_disconnect() __nvmet_rdma_queue_disconnect() queue_work(nvmet_wq, &queue->release_work) process_one_work() lock((wq_completion)nvmet-wq) <--------- 1st nvmet_rdma_release_queue_work() C. Recursive path (same worker): nvmet_rdma_release_queue_work() nvmet_rdma_free_queue() nvmet_sq_destroy() nvmet_ctrl_put() nvmet_ctrl_free() flush_work(&ctrl->async_event_work) __flush_work() touch_wq_lockdep_map() lock((wq_completion)nvmet-wq) <--------- 2nd Lockdep splat: ============================================ WARNING: possible recursive locking detected 6.19.0-rc3nvme+ #14 Tainted: G N -------------------------------------------- kworker/u192:42/44933 is trying to acquire lock: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90 but task is already holding lock: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660 3 locks held by kworker/u192:42/44933: #0: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660 #1: ffffc9000e6cbe28 ((work_completion)(&queue->release_work)){+.+.}-{0:0}, at: process_one_work+0x1c5/0x660 #2: ffffffff82d4db60 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x62/0x530 Workqueue: nvmet-wq nvmet_rdma_release_queue_work [nvmet_rdma] Call Trace: __flush_work+0x268/0x530 nvmet_ctrl_free+0x140/0x310 [nvmet] nvmet_cq_put+0x74/0x90 [nvmet] nvmet_rdma_free_queue+0x23/0xe0 [nvmet_rdma] nvmet_rdma_release_queue_work+0x19/0x50 [nvmet_rdma] process_one_work+0x206/0x660 worker_thread+0x184/0x320 kthread+0x10c/0x240 ret_from_fork+0x319/0x390 Move async event work to a dedicated nvmet-aen-wq to avoid reentrant flush on nvmet-wq.

Technical summary

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions

NVD · CPE data

Linux KernelOperating system

Affected:>= 5.15.42, < 5.16>= 5.17.10, < 5.18>= 5.18.1, < 6.12.80>= 6.13, < 6.18.21>= 6.19, < 6.19.11= 5.18= 7.0

CVSS breakdown

From the vector

Attack vector: Network
Complexity: Low
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Remediation

dbcve · scoped

Upgrade available Upgrade to 5.16 / 5.18 / 6.12.80 or later

Fixed in 5.165.186.12.80

Vendor patch git.kernel.org →

Recommended fix High confidence

6.12.80 or 6.18.21 (or any stable version >= 6.18.21)

1. Identify the current running kernel version using 'uname -r' or 'cat /proc/version'
2. Determine which major kernel branch you are running (e.g., 5.15.x, 5.17.x, 6.13.x)
3. If running kernel >= 5.15.42 and < 5.16: upgrade to 5.16 or later
4. If running kernel >= 5.17.10 and < 5.18: upgrade to 5.18 or later
5. If running kernel >= 5.18.1 and < 6.12.80: upgrade to 6.12.80 or later
6. If running kernel >= 6.13 and < 6.18.21: upgrade to 6.18.21 or later
7. After upgrade, verify the fix is present by checking kernel config includes CONFIG_NVME_TARGET and confirming the system boots without lockdep splats during NVMe target operations
8. Test NVMe target functionality (e.g., create/connect NVMe namespaces) to confirm the fix works correctly

Caveat Standard kernel upgrade risks apply - ensure compatibility with userspace tools and any kernel module dependencies

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

Scan for this in your stack

Free · runs locally

dbcve dependency scanner

Check whether your project pulls in CVE-2026-31557 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-31557 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2026-31557?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsUpgrade to 5.16 / 5.18 or later

Severity 7.5 High

Exploit likelihood EPSS, next 30 days 0.4%

Affects: Linux Kernel

Remediation

A high-priority fix

Get a fix

Estimated effortfrom ~11 hrs

ComplexityModerate

Typical engagementfrom $1,950

What a fix involves

We scope it with you and confirm a fixed quote
A specialist builds a reviewed fix
You deploy it to staging first
Optional re-test once it’s live

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2026-31557 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Remediation

References