External risk intelligence

Linux Kernel SCTP Use-After-Free Vulnerability.

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-74588

The vulnerability resides in the Linux kernel SCTP implementation. While SCTP is a network protocol, its exposure depends on whether a host runs an application utilizing SCTP that is reachable from the network. It is not inherently public-facing by design, but usage in network-exposed environments is plausible.

Use After Free

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability was identified in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. This flaw could potentially allow an attacker to exploit a memory corruption issue, leading to system instability or compromise. The main concern is to confirm if this specific technology is in use within our environment.

Kernel SCTP has a memory pointer issue.
It could lead to system instability or compromise.
Confirm relevance and exposure within our systems.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted network packets to a Linux system running the affected kernel. This could lead to a use-after-free condition within the kernel's Stream Control Transmission Protocol (SCTP) implementation, potentially allowing an attacker to crash the system or gain elevated privileges.

No specific access needed.
Triggered by network packets.
Leads to system instability or compromise.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could affect the behavior of network services by causing a use-after-free condition within the Linux kernel's SCTP implementation. When a chunk is moved between transport lists, its internal pointer might not be updated correctly. If a network peer later triggers a specific sequence of events, such as receiving a SACK that reneges on a transmission, this could lead to the kernel accessing freed memory, potentially causing instability or crashes in SCTP-related operations when supported by the advisory.

Kernel memory integrity.
Network data processing could be disrupted.
Potential for service instability or crashes.

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical vulnerability in the Linux kernel's SCTP module likely falls under the responsibility of infrastructure or platform teams managing Linux systems, with input from network or security teams for exposure assessment. The immediate first step is to identify all systems running the affected kernel, determine their network reachability and business criticality, and confirm the accountable system owner before planning remediation.

Infrastructure or platform teams own remediation.
Verify SCTP network exposure and criticality.
Plan coordinated updates during maintenance windows.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the Linux kernel SCTP component?

SCTP, or Stream Control Transmission Protocol, is a transport layer protocol used by the Linux kernel to manage reliable data connections between networked systems. It is often employed in high-performance or specialized applications that require multi-streaming or multi-homing capabilities, allowing a system to maintain connectivity across different network paths.

What does CVE-2026-74588 mean?

This CVE describes a use-after-free vulnerability, which is a class of memory corruption error. In this specific case, the kernel fails to update a pointer when moving data chunks between transport lists. If a network peer interacts with the system in a specific way, the kernel may attempt to read memory that has already been released, leading to potential system instability.

How is this vulnerability triggered?

An attacker triggers this flaw by sending specially crafted network packets to a Linux system using SCTP. The condition occurs during complex transmission scenarios where a peer reneges on previously acknowledged data. Note that normal packet resending does not trigger this issue, as the kernel correctly manages the chunk pointers during those standard operations.

Do I need to worry about this vulnerability?

According to Halo Surface Signal, risk depends on whether your Linux hosts actively use SCTP and are reachable from the network. Because the protocol is not inherently public-facing by design, you should determine if your applications utilize SCTP. If they do, the risk increases if those services are accessible to untrusted network traffic.

How should I respond to CVE-2026-74588?

Your first step is to inventory your infrastructure to identify which Linux systems are running an affected kernel. Once identified, evaluate whether those systems actually require SCTP functionality. Coordinate with your platform or infrastructure teams to plan and apply the necessary kernel updates during your next scheduled maintenance window to resolve the underlying memory management flaw.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.