# CVE-2025-22025: nfsd: put dl_stid if fail to queue dl_recall

> A memory leak in the Linux kernel NFS server allows attackers to cause denial of service by exhausting kernel memory through failed callback queueing.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 16 Apr 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2025-22025, DEBIAN-CVE-2025-22025, GHSA-jr2f-554p-cmvr, ROOT-OS-UBUNTU-2404-CVE-2025-22025, UBUNTU-CVE-2025-22025

## What is CVE-2025-22025?

CVE-2025-22025 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Apr 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:

nfsd: put dl_stid if fail to queue dl_recall

Before calling nfsd4_run_cb to queue dl_recall to the callback_wq, we
increment the reference count of dl_stid.
We expect that after the corresponding work_struct is processed, the
reference count of dl_stid will be decremented through the callback
function nfsd4_cb_recall_release.
However, if the call to nfsd4_run_cb fails, the incremented reference
count of dl_stid will not be decremented correspondingly, leading to the
following nfs4_stid leak:
unreferenced object 0xffff88812067b578 (size 344):
  comm "nfsd", pid 2761, jiffies 4295044002 (age 5541.241s)
  hex dump (first 32 bytes):
    01 00 00 00 6b 6b 6b 6b b8 02 c0 e2 81 88 ff ff  ....kkkk........
    00 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 ad 4e ad de  .kkkkkkk.....N..
  backtrace:
    kmem_cache_alloc+0x4b9/0x700
    nfsd4_process_open1+0x34/0x300
    nfsd4_open+0x2d1/0x9d0
    nfsd4_proc_compound+0x7a2/0xe30
    nfsd_dispatch+0x241/0x3e0
    svc_process_common+0x5d3/0xcc0
    svc_process+0x2a3/0x320
    nfsd+0x180/0x2e0
    kthread+0x199/0x1d0
    ret_from_fork+0x30/0x50
    ret_from_fork_asm+0x1b/0x30
unreferenced object 0xffff8881499f4d28 (size 368):
  comm "nfsd", pid 2761, jiffies 4295044005 (age 5541.239s)
  hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 30 4d 9f 49 81 88 ff ff  ........0M.I....
    30 4d 9f 49 81 88 ff ff 20 00 00 00 01 00 00 00  0M.I.... .......
  backtrace:
    kmem_cache_alloc+0x4b9/0x700
    nfs4_alloc_stid+0x29/0x210
    alloc_init_deleg+0x92/0x2e0
    nfs4_set_delegation+0x284/0xc00
    nfs4_open_delegation+0x216/0x3f0
    nfsd4_process_open2+0x2b3/0xee0
    nfsd4_open+0x770/0x9d0
    nfsd4_proc_compound+0x7a2/0xe30
    nfsd_dispatch+0x241/0x3e0
    svc_process_common+0x5d3/0xcc0
    svc_process+0x2a3/0x320
    nfsd+0x180/0x2e0
    kthread+0x199/0x1d0
    ret_from_fork+0x30/0x50
    ret_from_fork_asm+0x1b/0x30
Fix it by checking the result of nfsd4_run_cb and call nfs4_put_stid if
fail to queue dl_recall.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2025-22025?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-22025?

Apply the vendor's patch.

## Is CVE-2025-22025 being exploited?

There is no known exploitation of CVE-2025-22025 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-22025 and fix it if it is affected.

What it is: CVE-2025-22025 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Apr 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-2025-22025 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-22025/ (Markdown: https://insights.sbomify.com/CVE-2025-22025/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-22025
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-22025
- OSV: https://osv.dev/vulnerability/CVE-2025-22025

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-22025/
Summaries are generated and may contain mistakes; the official description above is the record.