Critical Linux Kernel CVE-2026-31431 Actively Exploited

THREAT INTELLIGENCE

Peer Review

4.8

Proven Trust

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Critical

CVE-2026-31431

Other

May 5, 2026

Executive Summary

CVE-2026-31431 is a critical Linux kernel logic flaw allowing local privilege escalation. It is actively exploited and listed in CISA’s KEV catalog.

Key Details

Affected Platform

Attack Surface

Recommended Action

Apply vendor patch

Affected Environment

Linux systems running kernel builds from 2017 to April 2026 are affected. Major distributions, including Ubuntu, RHEL and others, are in scope.

Operational Impact

Once local access exists, attackers can quickly gain root on affected hosts. This enables full system control, evasion of controls and persistence.

Technical Root Cause

The “Copy Fail” logic bug permits corruption of the kernel page cache for readable files. This enables modification of in-memory executables at runtime.

Recommended Mitigation

Identify affected Linux versions and apply vendor patches or mitigations after testing.
Enforce least privilege and keep endpoint and perimeter tools updated.

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Full Technical Report

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References

Refer to CISA KEV entries and national CSIRT advisories for status and guidance. Use vendor and research links provided for detailed technical mitigation steps.