CVE-2026-90246 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, AppArmor users and administrators, and security teams should be aware of this vulnerability and take necessary actions to verify and mitigate potential exposure. The vulnerability can be triggered by an unprivileged task in a matched-level nested namespace, not only by a globally privileged one. System logs should be verified for potential exploitation attempts. Affected product deployments should be identified, and

Why it matters

CVE-2026-90246 is an integer overflow vulnerability in the Linux kernel AppArmor component. Defenders should assess exposure, prioritize remediation, and verify system logs for potential exploitation attempts.

• Potential out-of-bounds read on the policy load path
• Possible denial of service (DoS) or information disclosure

Technical summary

The vulnerability is an integer overflow in the verify_tags() bounds check in the Linux kernel AppArmor component. An attacker-supplied count close to U32_MAX can cause an out-of-bounds read on the policy load path. The vulnerability can be triggered by an unprivileged task in a matched-level nested namespace. The patch for the Linux kernel AppArmor component has been applied to resolve the vulnerability. The addition is performed in u64 to prevent wrapping and restore the intended i + cnt < sets.size guarantee. The vulnerability has been resolved, and system logs should be verified for potential exploitation attempts.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the patch for the Linux kernel AppArmor component
• Verify the system's Linux kernel version and update if necessary
• Monitor system logs for potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD vulnerability detail page provide information on the vulnerability. Two source references from the Linux kernel Git repository are also available. The vulnerability has been resolved by performing the addition in u64 to prevent wrapping and restore the intended i + cnt < sets.size guarantee. The patch for the Linux kernel AppArmor component has been applied. System logs should be verified for potential exploitation attempts.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.