CVE-2026-74268 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel-based systems, operators of Linux-based infrastructure, security teams, and vulnerability management teams should assess exposure and prioritize patching to mitigate this vulnerability. They should verify Linux kernel versions, review system logs, and apply patches to prevent potential exploitation.

Why it matters

A vulnerability in the Linux kernel's TCP implementation could allow an attacker to trigger a warning when a child socket is force-closed. Defenders should prioritize verifying Linux kernel versions and applying patches to mitigate this vulnerability.

• Verify Linux kernel versions to determine if vulnerable
• Apply patches to mitigate this vulnerability
• Review system logs for warnings related to tcp_done() and tcp_set_state()

Technical summary

The Linux kernel's TCP implementation has a vulnerability that could allow an attacker to trigger a warning when a child socket is force-closed. The issue arises from the child socket inheriting the listener's bpf_sock_ops_cb_flags via sk_clone_lock(). If the child socket's setup fails, it is freed through put_and_exit, where inet_csk_prepare_forced_close() drops the socket lock and tcp_done() runs without it. This could potentially lead to a warning when tcp_done() -> tcp_set_state() calls tcp_call_bpf(), which expects the lock.

Defensive priority

Defenders should prioritize verifying Linux kernel versions and applying patches to mitigate this vulnerability.

Recommended defensive actions

• Verify Linux kernel versions and apply patches to mitigate this vulnerability
• Review system logs for warnings related to tcp_done() and tcp_set_state()
• Consider implementing compensating controls to detect and prevent potential exploitation
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source item provide details about the vulnerability, including its description, affected versions, and references to source code changes. Defenders should verify Linux kernel versions, review system logs for warnings related to tcp_done() and tcp_set_state(), and apply patches to mitigate this vulnerability. The vulnerability has been resolved in the Linux kernel, and defenders should prioritize patching to prevent potential exploitation.

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.