CVE-2026-98525 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, network administrators, and security teams responsible for Linux kernel deployments, operators of Linux-based systems, and security teams managing vulnerability assessments and patch management for Linux environments, platform administrators who manage Linux systems, and vulnerability management teams tracking Linux kernel vulnerabilities

Why it matters

This vulnerability in the Linux kernel's mctp implementation requires attention from Linux kernel developers, maintainers, and security teams to prevent potential unauthorized use of preallocated tags and denial of service. Verification of the fix and assessment of impact on specific deployments are necessary.

• Potential unauthorized use of preallocated tags by other sockets in the same network namespace
• Possible denial of service due to tag consumption
• Verification of socket tag list iteration in the `mctp_lookup_prealloc_tag()` function is required

Technical summary

The `mctp_lookup_prealloc_tag()` function iterates over the per-netns key list without checking if the socket matches the preallocated tag's socket. This allows any MCTP socket in the same network namespace to use and consume another socket's preallocated tag. The fix involves iterating over the socket's own tag list instead. This vulnerability in the Linux kernel's mctp implementation requires attention from Linux kernel developers, maintainers, and security teams to prevent potential unauthorized use of preallocated tags and denial of service. Verification of the fix and assessment of impact on specific deployments are necessary.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided patches to the Linux kernel
• Verify the socket's tag list iteration in the `mctp_lookup_prealloc_tag()` function
• Assess the vulnerability's impact on your specific Linux kernel deployment
• 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
• Review compensating controls for exposed systems while remediation is scheduled and verified
• 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 about the vulnerability, but the impact and affected versions are not explicitly stated. The Linux kernel's Git repository provides patches for this issue.

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.