---
title: "CVE-2026-89507: Linux Kernel RDMA/ucma - Denial of Service"
description: "Linux kernel RDMA/ucma contains a list corruption caused by improper locking in ucma_write_cm_event(), letting unprivileged users cause denial of service by wedging kernel mutex and corrupting event lists, exploit requires access to /dev/infiniband/rdma_cm device."
url: https://panop.io/threat-heartbeat/CVE-2026-89507/
---

# CVE-2026-89507 Linux Kernel RDMA/ucma - Denial of Service

Linux kernel RDMA/ucma contains a list corruption caused by improper locking in ucma\_write\_cm\_event(), letting unprivileged users cause denial of service by wedging kernel mutex and corrupting event lists, exploit requires access to /dev/infiniband/rdma\_cm device.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.13% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89507)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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

Published

11 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for ucma\_write\_cm\_event() locking.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-89507](https://nvd.nist.gov/vuln/detail/CVE-2026-89507)
- [https://git.kernel.org/stable/c/0be1955040a2eceed0ecfc387fdc92305411d273](https://git.kernel.org/stable/c/0be1955040a2eceed0ecfc387fdc92305411d273)
- [https://git.kernel.org/stable/c/4f8bb11dd2ff365e7cff1c9964ab4607292d364e](https://git.kernel.org/stable/c/4f8bb11dd2ff365e7cff1c9964ab4607292d364e)
- [https://git.kernel.org/stable/c/f4cc21c6a8e9d392871477f9fd98d68e5ad80272](https://git.kernel.org/stable/c/f4cc21c6a8e9d392871477f9fd98d68e5ad80272)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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