CVE-2026-23403

Received Received - Intake

Memory Leak in Linux Kernel AppArmor verify_header Function

Publication date: 2026-04-01

Last updated on: 2026-04-24

Assigner: kernel.org

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-04-01

Last Modified

2026-04-24

Generated

2026-07-06

AI Q&A

2026-04-01

EPSS Evaluated

2026-07-05

NVD

CVE-2026-23403

EUVD

EUVD-2026-17831

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	3.12
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	From 6.2 (inc) to 6.6.130 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.77 (exc)
linux	linux_kernel	From 5.11 (inc) to 5.15.203 (exc)
linux	linux_kernel	From 3.12.1 (inc) to 5.10.253 (exc)
linux	linux_kernel	From 5.16 (inc) to 6.1.169 (exc)
linux	linux_kernel	From 6.13 (inc) to 6.18.18 (exc)
linux	linux_kernel	From 6.19 (inc) to 6.19.8 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-401	The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Attack-Flow Graph

Executive Summary

This vulnerability is a memory leak in the Linux kernel's AppArmor component, specifically in the verify_header function.

The function incorrectly sets the pointer *ns to NULL on every call, which causes the namespace string allocated in previous iterations to be leaked when multiple profiles are unpacked.

Additionally, this incorrect assignment breaks namespace consistency checking because *ns is always NULL during the comparison.

The fix involves removing the incorrect assignment, relying instead on the caller (aa_unpack) to initialize *ns to NULL once before the loop, which is sufficient.

Impact Analysis

This vulnerability can lead to a memory leak in the Linux kernel when multiple AppArmor profiles are unpacked.

Memory leaks can degrade system performance over time by consuming more memory than necessary.

Furthermore, the broken namespace consistency checking could potentially cause incorrect security profile behavior, which might affect the enforcement of security policies.

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