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Mallory
Medium

Linux kernel AppArmor recursive profile removal stack exhaustion

IdentifiersCVE-2026-23404CWE-674

CVE-2026-23404 is a local denial-of-service vulnerability in the Linux kernel AppArmor subsystem. The flaw is in the profile removal logic for nested AppArmor profiles: removing an ancestor profile causes recursive traversal and deletion of descendant profiles via __remove_profile() and __aa_profile_list_release(). If an attacker creates a deeply nested hierarchy of subprofiles and then removes the top-level profile, the recursive call chain can exhaust the kernel stack and crash the system. The upstream fix replaces the recursive removal logic with an iterative approach in __remove_profile() that repeatedly removes leaf profiles until the subtree is fully deleted, preserving semantics while avoiding unbounded recursion.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can exhaust kernel stack space and crash the system, resulting in a local denial of service. Available supporting content indicates high availability impact with no demonstrated confidentiality or integrity impact, and the issue is believed to be DoS-only rather than a local privilege escalation.

Mitigation

If you can’t patch tonight, do this now.

Until patched, reduce exposure by restricting who can load and remove AppArmor profiles or create deeply nested AppArmor subprofile hierarchies. Limit local low-privilege access to AppArmor management interfaces and avoid delegating profile-management capabilities to untrusted users or containers. These are partial mitigations only; the definitive fix is a patched kernel.

Remediation

Patch, then assume compromise.

Apply a kernel update that includes the AppArmor fix for CVE-2026-23404. The upstream remediation replaces recursive nested-profile deletion with an iterative removal algorithm in __remove_profile(). Vendor advisories indicate fixes have been shipped across multiple SUSE kernel package lines; affected systems should be updated to the vendor-provided fixed kernel and rebooted as required.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
LinuxLinux Kerneloperating_system

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Threat actor evidence

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Detection signatures

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Social activity

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