CVE-2026-64551 Linux CVE debrief

Who should care

System administrators and users of Linux systems should be aware of this vulnerability and take steps to patch it. The vulnerability can be exploited by an unprivileged process using a raw SCTP socket in a user and network namespace.

Technical summary

The Linux kernel's SCTP implementation has a vulnerability that allows for the leakage of uninitialized memory. This occurs when an ERROR chunk with a STALE_COOKIE cause is received in the COOKIE_ECHOED state. The vulnerability is caused by not validating the STALE_COOKIE cause length before reading the staleness field. The fix involves validating the STALE_COOKIE cause length before reading the staleness field.

Defensive priority

High priority should be given to patching this vulnerability as it has a high CVSS score of 9.1 and can be exploited by an unprivileged process using a raw SCTP socket in a user and network namespace.

Recommended defensive actions

• Apply the patch to validate STALE_COOKIE cause length
• Restrict access to SCTP sockets to privileged processes
• Monitor for unusual SCTP activity
• 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 vulnerability exists in the Linux kernel's SCTP implementation. An ERROR chunk with a STALE_COOKIE cause received in the COOKIE_ECHOED state can cause the leakage of uninitialized memory. The fix validates the STALE_COOKIE cause length before reading the staleness field. Evidence is based on official CVE and NVD records, and Linux kernel source code references.

Official resources