---
title: "CVE-2026-98253: Linux Kernel RDMA/ucma - Use After Free"
description: "Linux kernel RDMA/ucma contains a race condition caused by improper mutex handling in rdma_join_multicast and rdma_leave_multicast functions, letting concurrent join and leave calls cause use-after-free, exploit requires concurrent multicast join calls."
url: https://panop.io/threat-heartbeat/CVE-2026-98253/
---

# CVE-2026-98253 Linux Kernel RDMA/ucma - Use After Free

Linux kernel RDMA/ucma contains a race condition caused by improper mutex handling in rdma\_join\_multicast and rdma\_leave\_multicast functions, letting concurrent join and leave calls cause use-after-free, exploit requires concurrent multicast join calls.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.14% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-98253)

## Details

Type

Use After Free

Impact

Use After Free, Denial Of Service, Privilege Escalation

CVSS vector

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

Published

6 October 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix.

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-2026-98253](https://nvd.nist.gov/vuln/detail/CVE-2026-98253)
- [https://git.kernel.org/stable/c/29b9ed83d8bfab5c6e11fcbf1aa836aa4ae26cb9](https://git.kernel.org/stable/c/29b9ed83d8bfab5c6e11fcbf1aa836aa4ae26cb9)
- [https://git.kernel.org/stable/c/43c4e24bd10370fc976f6220518049ce71419399](https://git.kernel.org/stable/c/43c4e24bd10370fc976f6220518049ce71419399)
- [https://git.kernel.org/stable/c/52172e11bd074ccaded21740ffeb67123f01dd00](https://git.kernel.org/stable/c/52172e11bd074ccaded21740ffeb67123f01dd00)
- [https://git.kernel.org/stable/c/662ade4de9ff5eceb0820a9f8e9fac70ba6a815b](https://git.kernel.org/stable/c/662ade4de9ff5eceb0820a9f8e9fac70ba6a815b)
- [https://git.kernel.org/stable/c/83610ee5e498fa5bfcb80031d2b959baea276bf6](https://git.kernel.org/stable/c/83610ee5e498fa5bfcb80031d2b959baea276bf6)
- [https://git.kernel.org/stable/c/ae805d204cf1f15b87d1bf3529b4c649f3519420](https://git.kernel.org/stable/c/ae805d204cf1f15b87d1bf3529b4c649f3519420)
- [https://git.kernel.org/stable/c/01cbdb724c584d7772fd25af2e4dfdf8527ce0d5](https://git.kernel.org/stable/c/01cbdb724c584d7772fd25af2e4dfdf8527ce0d5)
- [https://git.kernel.org/stable/c/01e29d0d78a8f66f221625720a04939eef5ec1f6](https://git.kernel.org/stable/c/01e29d0d78a8f66f221625720a04939eef5ec1f6)

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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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