CVE-2026-74600 Linux CVE debrief

Who should care

Linux kernel system administrators and security teams should assess exposure and apply patches to prevent potential exploitation attempts. They should verify Linux kernel versions and configurations to ensure patches are applied and monitor for potential exploitation attempts to detect potential attacks. Additionally, they should prioritize patching for Linux kernel systems and review compensating controls for exposed systems while remediation is scheduled

Why it matters

CVE-2026-74600 is a Linux kernel vulnerability that can be exploited by an unprivileged process to overflow file_map_count and hit the existing BUG_ON(). The issue has been resolved by skipping special zero mappings in the user page-table accounting paths. Linux kernel system administrators and security teams should assess exposure and apply patches to prevent potential exploitation attempts.

• Verify Linux kernel versions and configurations to ensure patches are applied
• Monitor for potential exploitation attempts to detect potential attacks
• Assess exposure and prioritize patching for Linux kernel systems

Technical summary

The Linux kernel vulnerability (CVE-2026-74600) is caused by the page_table_check_set() and page_table_check_clear() functions accounting mappings based on PageAnon(). Shared zero-page PTEs and huge zero PMDs are special mappings that can still be accounted as file-backed pages, potentially overflowing file_map_count and hitting the existing BUG_ON(). The issue is resolved by skipping special zero mappings in the user page-table accounting paths.

Defensive priority

Assess exposure and apply patches for Linux kernel systems

Recommended defensive actions

• Assess exposure and apply patches for Linux kernel systems
• Verify Linux kernel versions and configurations
• Monitor 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 entry provide details on the vulnerability and its resolution. Multiple source references from the Linux kernel Git repository are available. The issue is caused by the page_table_check_set() and page_table_check_clear() functions accounting mappings based on PageAnon(). Shared zero-page PTEs and huge zero PMDs are special mappings that can still be accounted as file-backed pages, potentially overflowing file_map_count and hitting the existing BUG_ON(). The resolution skips special zero mappings in the user page

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.