CVE-2026-89477 Linux CVE debrief

Who should care

Linux kernel developers, administrators, and users who rely on SCTP protocol, as well as operators and security teams responsible for managing and securing Linux-based systems, should assess exposure and prioritize patching to prevent potential denial of service and remote code execution attacks.

Why it matters

CVE-2026-89477 is a null pointer dereference vulnerability in the Linux kernel's SCTP implementation. Defenders should care because it can lead to a denial of service and potentially allow for remote code execution, although further verification is needed. Linux kernel developers, administrators, and users who rely on SCTP protocol should assess exposure and prioritize patching.

• Denial of Service (DoS) via null pointer dereference
• Potential for remote code execution requires further verification
• Need for patching and remediation prioritization

Technical summary

The vulnerability exists in the Linux kernel's SCTP implementation, specifically in the sctp_process_strreset_outreq(), sctp_process_strreset_addstrm_out(), and sctp_process_strreset_resp() functions. A null pointer dereference occurs when a stream reconfiguration request is completed on an untransmitted chunk. This can happen when an unprivileged process removes an address and then requests a stream reset, causing the kernel to panic from softirq. A remote peer can also trigger this vulnerability by sending a specially crafted packet. The vulnerability can be mitigated by reviewing and applying the provided kernel patches, restricting access to the SCTP protocol, and monitoring network traffic for suspicious

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided kernel patches to fix the vulnerability
• Restrict access to the SCTP protocol to only trusted sources
• Monitor network traffic for suspicious SCTP packets
• Consider compensating controls for exposed systems while remediation is scheduled and verified
• Review 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 is caused by a null pointer dereference in the sctp_process_strreset_outreq(), sctp_process_strreset_addstrm_out(), and sctp_process_strreset_resp() functions. The vulnerability can be triggered by an unprivileged process or a remote peer.

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.