Bug 2453799 (CVE-2026-23404)

Summary: CVE-2026-23404 kernel: apparmor: replace recursive profile removal with iterative approach
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel's AppArmor security module. A local user could trigger a denial of service by initiating a recursive profile removal operation with deeply nested profiles. This recursive process can lead to kernel stack exhaustion, causing the system to crash.
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Description OSIDB Bzimport 2026-04-01 10:02:24 UTC
In the Linux kernel, the following vulnerability has been resolved:

apparmor: replace recursive profile removal with iterative approach

The profile removal code uses recursion when removing nested profiles,
which can lead to kernel stack exhaustion and system crashes.

Reproducer:
  $ pf='a'; for ((i=0; i<1024; i++)); do
      echo -e "profile $pf { \n }" | apparmor_parser -K -a;
      pf="$pf//x";
  done
  $ echo -n a > /sys/kernel/security/apparmor/.remove

Replace the recursive __aa_profile_list_release() approach with an
iterative approach in __remove_profile(). The function repeatedly
finds and removes leaf profiles until the entire subtree is removed,
maintaining the same removal semantic without recursion.