CVE-2026-98643 Linux CVE debrief

Who should care

Linux kernel administrators, security teams, and developers using sockops programs in their systems should assess exposure and prioritize verification of affected systems. This includes operators managing Linux kernel deployments, platform administrators, vulnerability management teams, and security teams responsible for monitoring and mitigating potential threats.

Why it matters

CVE-2026-98643 is a vulnerability in the Linux kernel's bpf sock_ops program that can lead to out-of-bounds reads, potentially leaking sensitive information. Linux kernel administrators and security teams should assess exposure and prioritize verification of affected systems.

• Potential memory leaks due to out-of-bounds reads
• Unexpected behavior or crashes from accessing adjacent memory
• Increased risk of information disclosure through leaked memory

Technical summary

The Linux kernel's bpf sock_ops program has a vulnerability that allows for an out-of-bounds read of rtt_min. This occurs when a sockops prog reads skops->rtt_min without checking the sk type, specifically on the tcp_conn_request() path where sock_ops->sk is a request_sock. The fix involves using SOCK_OPS_GET_FIELD() to guard the cast and ensure proper checks. This vulnerability can lead to potential memory leaks due to out-of-bounds reads, unexpected behavior or crashes from accessing adjacent memory, and increased risk of information disclosure through leaked memory. Linux kernel administrators and security teams should assess exposure and prioritize verification of affected systems, especially those with

Defensive priority

Linux kernel administrators and security teams should assess exposure and prioritize verification of affected systems, especially those with sockops programs. Remediation involves applying the provided patch to ensure proper checks are in place.

Recommended defensive actions

• Assess exposure of Linux kernel systems using sockops programs
• Verify affected systems and apply the provided patch
• Monitor for potential memory leaks or unexpected behavior
• 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 source metadata indicate a fix has been applied to the Linux kernel to address the out-of-bounds read vulnerability in sock_ops. Official references from the Linux kernel Git repository are provided.

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.