---
title: "CVE-2026-99042: Linux Kernel - Broken Access Control"
description: "Linux kernel io_uring/net contains a bypass vulnerability caused by incorrect threshold for populating CONNECT filter fields in sockaddr_in6, letting attackers bypass IPv6 port/address filtering, exploit requires crafted IPv6 connect requests with 24-byte sockaddr_in6."
url: https://panop.io/threat-heartbeat/CVE-2026-99042/
---

# CVE-2026-99042 Linux Kernel - Broken Access Control

Linux kernel io\_uring/net contains a bypass vulnerability caused by incorrect threshold for populating CONNECT filter fields in sockaddr\_in6, letting attackers bypass IPv6 port/address filtering, exploit requires crafted IPv6 connect requests with 24-byte sockaddr\_in6.

CVSS base score 8.4 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.21% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-99042)

## Details

Type

Broken Access Control

Impact

Broken Access Control

CVSS vector

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

Published

23 October 2026

Updated

25 October 2026

## Vendor fix

Update to Linux kernel version 7.3-rc6 or later where the threshold mismatch is fixed.

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-2026-99042](https://nvd.nist.gov/vuln/detail/CVE-2026-99042)
- [https://git.kernel.org/stable/c/596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5](https://git.kernel.org/stable/c/596a955d2d01b7e29d9fed60ebcf7c4ba518b8e5)
- [https://git.kernel.org/stable/c/aa5d5f8e502318e783545ba5d04bb40130b83e20](https://git.kernel.org/stable/c/aa5d5f8e502318e783545ba5d04bb40130b83e20)

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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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