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PatchSiren cyber security CVE debrief

CVE-2026-45893 Linux CVE debrief

A vulnerability in the Linux kernel's AppArmor security module has been resolved. The issue involved unaligned memory access when creating tables from data blobs that may originate from userspace. The fix optimizes the copying process to avoid unaligned memory accesses, which could lead to undefined behavior or potential crashes on architectures sensitive to alignment. The patch was committed to the stable kernel tree on 2026-05-27.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-27
Original CVE updated
2026-05-27
Advisory published
2026-05-27
Advisory updated
2026-05-27

Who should care

Linux system administrators running AppArmor, kernel maintainers, security teams monitoring kernel LSM (Linux Security Modules) vulnerabilities, and organizations deploying Linux on architectures with strict memory alignment requirements

Technical summary

The vulnerability exists in AppArmor's table creation code path where data blobs from userspace are processed. On architectures with strict alignment requirements, unaligned memory accesses can cause exceptions, data corruption, or undefined behavior. The fix implements optimized copying that ensures proper alignment during table construction from potentially unaligned source memory.

Defensive priority

medium

Recommended defensive actions

  • Apply the relevant stable kernel patch for your kernel version
  • Monitor kernel stable updates for AppArmor fixes
  • Review AppArmor policy loading mechanisms for unaligned access patterns
  • Validate kernel builds on architectures with strict alignment requirements (e.g., ARM, RISC-V, SPARC)
  • Consider enabling kernel hardening features that detect or prevent unaligned access

Evidence notes

The CVE description and kernel commit messages confirm this is a fix for unaligned memory access in AppArmor table creation. The source blob may come from userspace, making alignment unpredictable. Four stable kernel commits are referenced, indicating backports to multiple kernel versions.

Official resources

2026-05-27