CVE-2026-23407

Local privilege escalation via malformed AppArmor DFA

Published Apr 1, 2026 · Updated Apr 1, 2026

Out-of-bounds access in affected Linux kernels allows local users to escalate privileges through a crafted AppArmor policy. In verify_dfa(), a differential-chain DEFAULT_TABLE value at or above state_count is used as an array index without validation, causing kernel heap reads and writes. Loading the policy requires CAP_MAC_ADMIN, obtainable by unprivileged local users when unprivileged_userns_apparmor_policy is enabled; successful corruption can disclose kernel data, crash the system, or enable kernel code execution.

CVSS severity7.8
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in affected Linux kernels allows local users to escalate privileges through a crafted AppArmor policy. In verify_dfa(), a differential-chain DEFAULT_TABLE value at or above state_count is used as an array index without validation, causing kernel heap reads and writes. Loading the policy requires CAP_MAC_ADMIN, obtainable by unprivileged local users when unprivileged_userns_apparmor_policy is enabled; successful corruption can disclose kernel data, crash the system, or enable kernel code execution.

The record

CVE
CVE-2026-23407
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-125, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <5a68e46dfe0c8c8ffc6f425ebc4cae6238566ecc
  2. Affected versionversion=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <76b4d36c5122866452d34d8f79985e191f9c3831
  3. Affected versionversion=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <7c7cf05e0606f554c467e3a4dc49e2e578a755b4
  4. Affected versionversion=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <d352873bbefa7eb39995239d0b44ccdf8aaa79a4
  5. Affected versionversion=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <f39e126e56c6ec1930fae51ad6bca3dae2a4c3ed
  6. Affected versionversion=4.17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <5a68e46dfe0c8c8ffc6f425ebc4cae6238566ecc; version=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <76b4d36c5122866452d34d8f79985e191f9c3831; version=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <7c7cf05e0606f554c467e3a4dc49e2e578a755b4; version=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <d352873bbefa7eb39995239d0b44ccdf8aaa79a4; version=031dcc8f4e84fea37dc6f78fdc7288aa7f8386c3 <f39e126e56c6ec1930fae51ad6bca3dae2a4c3ed; version=4.17

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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