# CVE-2025-40261: nvme: nvme-fc: Ensure ->ioerr_work is cancelled in nvme_fc_delete_ctrl()

> A race condition in the Linux kernel NVMe FC driver can cause a use-after-free, leading to a kernel crash and denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-71366, BELL-CVE-2025-40261, DEBIAN-CVE-2025-40261, GHSA-9x2f-7mf8-f579, ROOT-OS-DEBIAN-12-CVE-2025-40261, ROOT-OS-DEBIAN-13-CVE-2025-40261, ROOT-OS-UBUNTU-2204-CVE-2025-40261, ROOT-OS-UBUNTU-2404-CVE-2025-40261, UBUNTU-CVE-2025-40261

## What is CVE-2025-40261?

CVE-2025-40261 is a critical use after free vulnerability in Linux, published on 4 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

nvme: nvme-fc: Ensure ->ioerr_work is cancelled in nvme_fc_delete_ctrl()

nvme_fc_delete_assocation() waits for pending I/O to complete before
returning, and an error can cause ->ioerr_work to be queued after
cancel_work_sync() had been called.  Move the call to cancel_work_sync() to
be after nvme_fc_delete_association() to ensure ->ioerr_work is not running
when the nvme_fc_ctrl object is freed.  Otherwise the following can occur:

[ 1135.911754] list_del corruption, ff2d24c8093f31f8->next is NULL
[ 1135.917705] ------------[ cut here ]------------
[ 1135.922336] kernel BUG at lib/list_debug.c:52!
[ 1135.926784] Oops: invalid opcode: 0000 [#1] SMP NOPTI
[ 1135.931851] CPU: 48 UID: 0 PID: 726 Comm: kworker/u449:23 Kdump: loaded Not tainted 6.12.0 #1 PREEMPT(voluntary)
[ 1135.943490] Hardware name: Dell Inc. PowerEdge R660/0HGTK9, BIOS 2.5.4 01/16/2025
[ 1135.950969] Workqueue:  0x0 (nvme-wq)
[ 1135.954673] RIP: 0010:__list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1135.961041] Code: c7 c7 98 68 72 94 e8 26 45 fe ff 0f 0b 48 c7 c7 70 68 72 94 e8 18 45 fe ff 0f 0b 48 89 fe 48 c7 c7 80 69 72 94 e8 07 45 fe ff <0f> 0b 48 89 d1 48 c7 c7 a0 6a 72 94 48 89 c2 e8 f3 44 fe ff 0f 0b
[ 1135.979788] RSP: 0018:ff579b19482d3e50 EFLAGS: 00010046
[ 1135.985015] RAX: 0000000000000033 RBX: ff2d24c8093f31f0 RCX: 0000000000000000
[ 1135.992148] RDX: 0000000000000000 RSI: ff2d24d6bfa1d0c0 RDI: ff2d24d6bfa1d0c0
[ 1135.999278] RBP: ff2d24c8093f31f8 R08: 0000000000000000 R09: ffffffff951e2b08
[ 1136.006413] R10: ffffffff95122ac8 R11: 0000000000000003 R12: ff2d24c78697c100
[ 1136.013546] R13: fffffffffffffff8 R14: 0000000000000000 R15: ff2d24c78697c0c0
[ 1136.020677] FS:  0000000000000000(0000) GS:ff2d24d6bfa00000(0000) knlGS:0000000000000000
[ 1136.028765] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1136.034510] CR2: 00007fd207f90b80 CR3: 000000163ea22003 CR4: 0000000000f73ef0
[ 1136.041641] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1136.048776] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
[ 1136.055910] PKRU: 55555554
[ 1136.058623] Call Trace:
[ 1136.061074]  <TASK>
[ 1136.063179]  ? show_trace_log_lvl+0x1b0/0x2f0
[ 1136.067540]  ? show_trace_log_lvl+0x1b0/0x2f0
[ 1136.071898]  ? move_linked_works+0x4a/0xa0
[ 1136.075998]  ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.081744]  ? __die_body.cold+0x8/0x12
[ 1136.085584]  ? die+0x2e/0x50
[ 1136.088469]  ? do_trap+0xca/0x110
[ 1136.091789]  ? do_error_trap+0x65/0x80
[ 1136.095543]  ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.101289]  ? exc_invalid_op+0x50/0x70
[ 1136.105127]  ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.110874]  ? asm_exc_invalid_op+0x1a/0x20
[ 1136.115059]  ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.120806]  move_linked_works+0x4a/0xa0
[ 1136.124733]  worker_thread+0x216/0x3a0
[ 1136.128485]  ? __pfx_worker_thread+0x10/0x10
[ 1136.132758]  kthread+0xfa/0x240
[ 1136.135904]  ? __pfx_kthread+0x10/0x10
[ 1136.139657]  ret_from_fork+0x31/0x50
[ 1136.143236]  ? __pfx_kthread+0x10/0x10
[ 1136.146988]  ret_from_fork_asm+0x1a/0x30
[ 1136.150915]  </TASK>

## Which versions are affected by CVE-2025-40261?


## How do I fix CVE-2025-40261?

Apply the vendor's patch.

## Is CVE-2025-40261 being exploited?

There is no known exploitation of CVE-2025-40261 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40261 and fix it if it is affected.

What it is: CVE-2025-40261 is a critical use after free vulnerability in Linux, published on 4 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-40261 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-40261/ (Markdown: https://insights.sbomify.com/CVE-2025-40261/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40261
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40261
- OSV: https://osv.dev/vulnerability/CVE-2025-40261

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40261/
Summaries are generated and may contain mistakes; the official description above is the record.