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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-23409 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: apparmor: fix differential encoding verification Differential encoding allows loops to be created if it is abused. To prevent this the unpack should verify that a diff-encode chain terminates. Unfortunately the differential encode verification had two bugs. 1. it conflated states that had gone through check and already been marked, with states that were currently being checked and marked. This means that loops in the current chain being verified are treated as a chain that has already been verified. 2. the order bailout on already checked states compared current chain check iterators j,k instead of using the outer loop iterator i. Meaning a step backwards in states in the current chain verification was being mistaken for moving to an already verified state. Move to a double mark scheme where already verified states get a different mark, than the current chain being kept. This enables us to also drop the backwards verification check that was the cause of the second error as any already verified state is already marked.


Metrics

 
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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/0fab44285445e9012674396d5c1236a67da518e0 kernel.org Patch 
https://git.kernel.org/stable/c/1439150cd3c411228b387ab5efca92199d2a659a kernel.org Patch 
https://git.kernel.org/stable/c/1ff4857fac56ac5a90ee63b24db05fa5e91a45aa kernel.org Patch 
https://git.kernel.org/stable/c/34fc60b125ed1d4eb002c76b0664bf0619492167 kernel.org Patch 
https://git.kernel.org/stable/c/39440b137546a3aa383cfdabc605fb73811b6093 kernel.org Patch 
https://git.kernel.org/stable/c/623a9d211bbbb031bb1cbdb38b23487648167f8a kernel.org Patch 
https://git.kernel.org/stable/c/f90e3ecd9e1ed69f1a370f866ceed1f104f3ab4a kernel.org Patch 
https://git.kernel.org/stable/c/ff7c73744fafe944ed9a7b2b7cf6c8d5557a3d84 kernel.org Patch 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') cwe source acceptance level NIST  

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-23409
NVD Published Date:
04/01/2026
NVD Last Modified:
04/24/2026
Source:
kernel.org