# CVE-2025-21805: RDMA/rtrs: Add missing deinit() call

> A missing deinitialization call in the Linux kernel RDMA subsystem causes list corruption and potential crashes during repeated connection cycles.

- **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:** 27 Feb 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-21805, DEBIAN-CVE-2025-21805, GHSA-hg55-7j9j-f4rq, UBUNTU-CVE-2025-21805

## What is CVE-2025-21805?

CVE-2025-21805 is a critical memory corruption vulnerability in Linux kernel, published on 27 Feb 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:

RDMA/rtrs: Add missing deinit() call

A warning is triggered when repeatedly connecting and disconnecting the
rnbd:
 list_add corruption. prev->next should be next (ffff88800b13e480), but was ffff88801ecd1338. (prev=ffff88801ecd1340).
 WARNING: CPU: 1 PID: 36562 at lib/list_debug.c:32 __list_add_valid_or_report+0x7f/0xa0
 Workqueue: ib_cm cm_work_handler [ib_cm]
 RIP: 0010:__list_add_valid_or_report+0x7f/0xa0
  ? __list_add_valid_or_report+0x7f/0xa0
  ib_register_event_handler+0x65/0x93 [ib_core]
  rtrs_srv_ib_dev_init+0x29/0x30 [rtrs_server]
  rtrs_ib_dev_find_or_add+0x124/0x1d0 [rtrs_core]
  __alloc_path+0x46c/0x680 [rtrs_server]
  ? rtrs_rdma_connect+0xa6/0x2d0 [rtrs_server]
  ? rcu_is_watching+0xd/0x40
  ? __mutex_lock+0x312/0xcf0
  ? get_or_create_srv+0xad/0x310 [rtrs_server]
  ? rtrs_rdma_connect+0xa6/0x2d0 [rtrs_server]
  rtrs_rdma_connect+0x23c/0x2d0 [rtrs_server]
  ? __lock_release+0x1b1/0x2d0
  cma_cm_event_handler+0x4a/0x1a0 [rdma_cm]
  cma_ib_req_handler+0x3a0/0x7e0 [rdma_cm]
  cm_process_work+0x28/0x1a0 [ib_cm]
  ? _raw_spin_unlock_irq+0x2f/0x50
  cm_req_handler+0x618/0xa60 [ib_cm]
  cm_work_handler+0x71/0x520 [ib_cm]

Commit 667db86bcbe8 ("RDMA/rtrs: Register ib event handler") introduced a
new element .deinit but never used it at all. Fix it by invoking the
`deinit()` to appropriately unregister the IB event handler.

## Which versions are affected by CVE-2025-21805?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-21805?

Apply the vendor's patch.

## Is CVE-2025-21805 being exploited?

There is no known exploitation of CVE-2025-21805 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-2025-21805 and fix it if it is affected.

What it is: CVE-2025-21805 is a critical memory corruption vulnerability in Linux kernel, published on 27 Feb 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-2025-21805 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-2025-21805/ (Markdown: https://insights.sbomify.com/CVE-2025-21805/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21805
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21805
- OSV: https://osv.dev/vulnerability/CVE-2025-21805

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21805/
Summaries are generated and may contain mistakes; the official description above is the record.