CVE intelligence

CVE-2026-23403

Vulnerability intelligence

Published Apr 1, 2026Sources checked Nov 11, 2026

5.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-23403 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 30, 2026

CBL-Mariner Releases Release Notes

Vendor-listed releases

6.6.130.1-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-23403?

In the Linux kernel, the following vulnerability has been resolved:

apparmor: fix memory leak in verify_header

The function sets `*ns = NULL` on every call, leaking the namespace string allocated in previous iterations when multiple profiles are unpacked. This also breaks namespace consistency checking since *ns is always NULL when the comparison is made.

Remove the incorrect assignment. The caller (aa_unpack) initializes *ns to NULL once before the loop, which is sufficient.

Source: NVD