---
title: "CVE-2026-90173: Linux Kernel - Use After Free"
description: "Linux kernel contains a use-after-free vulnerability in smbdirect caused by improper teardown of completion queues with ib_destroy_cq(), letting attackers cause kernel memory corruption, exploit requires triggering late completion after queue destruction."
url: https://panop.io/threat-heartbeat/CVE-2026-90173/
---

# CVE-2026-90173 Linux Kernel - Use After Free

Linux kernel contains a use-after-free vulnerability in smbdirect caused by improper teardown of completion queues with ib\_destroy\_cq(), letting attackers cause kernel memory corruption, exploit requires triggering late completion after queue destruction.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.55% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-90173)

## Details

Type

Use After Free

Impact

Denial Of Service, Privilege Escalation

CVSS vector

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

Published

17 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix that uses ib\_free\_cq() to properly free completion queues.

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-2026-90173](https://nvd.nist.gov/vuln/detail/CVE-2026-90173)
- [https://git.kernel.org/stable/c/8a953b1a47fffb71e70767bc1e914401e3c2f27f](https://git.kernel.org/stable/c/8a953b1a47fffb71e70767bc1e914401e3c2f27f)
- [https://git.kernel.org/stable/c/fe2c0cacbcff9d56c03b296f68f22151c4223b04](https://git.kernel.org/stable/c/fe2c0cacbcff9d56c03b296f68f22151c4223b04)

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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

Panop answers these inside your environment, for this CVE and every other finding.

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