External risk intelligence

Linux Kernel SCTP Malformed Cookie Out-of-Bounds Read

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-53224

The vulnerability exists in the Linux kernel's SCTP implementation, which handles network traffic. While SCTP is a transport-layer protocol often used for specific services that may be exposed to the internet, it is not universally deployed on public-facing interfaces by default, and its reachability depends heavily on the specific applications and network configurations utilizing SCTP.

Out-of-bounds Read

Linux Kernel

2.6.12.1 to before 6.18.366.19 to before 7.0.132.6.127.1

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 has been identified in the Linux kernel's Secure Stream Transmission Protocol (SCTP) implementation that could allow for out-of-bounds reads due to improper handling of malformed data packets. This could potentially impact systems that utilize SCTP for network communication, though its direct exposure and impact will vary based on specific configurations and usage.

Malformed network packets can trigger memory access errors.
Affects core Linux kernel network functionality.
Confirm relevance to understand potential exposure.

Attack Path

How an attacker could exploit the issue

An attacker could send specially crafted network packets to the Linux kernel's SCTP (Stream Control Transmission Protocol) implementation. By sending a malformed COOKIE_ECHO packet with a truncated INIT chunk or an oversized address list, an attacker could cause the kernel to read beyond allocated memory, potentially leading to a crash or information disclosure. This can occur when cookie authentication is disabled.

No authentication or special access required.
Malicious SCTP packets trigger the vulnerability.
Memory corruption and denial of service risks.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, a malformed network request could lead to out-of-bounds reads in the Linux kernel's SCTP implementation. This could affect system stability and potentially allow for unauthorized access to memory.

System memory.
Malformed network packets.
System instability or crashes.

Operational Fix

Recommended remediation, mitigation, and detection steps

Infrastructure or platform teams are likely responsible for managing the Linux kernel and its components, including the SCTP module. The first practical step is to identify all systems running the affected kernel version, determine if SCTP is enabled and exposed externally, and ascertain if it's a business-critical service. This information is crucial for prioritizing remediation efforts and engaging the appropriate system owners.

Kernel and platform teams own this issue.
Verify SCTP usage and external reachability.
Plan kernel 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 within the Linux kernel. It allows applications to send data streams across a network, providing features like multi-homing and multi-streaming. It is typically used for specialized telecommunications, signaling, or high-reliability network applications rather than standard web traffic.

What does this vulnerability mean for CVE-2026-53224?

This vulnerability is an out-of-bounds read error. It occurs because the kernel's SCTP implementation fails to properly verify the size of data structures embedded within incoming connection packets. Because the code doesn't check if the provided data matches the expected format, the kernel may attempt to read memory locations outside of the allocated buffer, potentially revealing system information or causing a crash.

How does an attacker trigger this bug?

An attacker triggers this by sending a specially crafted, malformed COOKIE_ECHO packet to a target system. The vulnerability specifically activates when SCTP cookie authentication is disabled, allowing the attacker to provide truncated INIT headers or oversized address lists that force the kernel to access unauthorized memory. Valid, properly formed SCTP packets do not trigger this issue.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal indicates that your risk depends on whether your infrastructure uses the Linux kernel's SCTP implementation and if it is reachable over the network. Since SCTP is not always enabled or exposed on public-facing interfaces by default, the vulnerability's relevance is tied to your specific application configuration and whether those services are accessible to the internet.

What should I do to address CVE-2026-53224?

Your first step is to audit your environment to identify systems running the affected Linux kernel that have SCTP enabled. Determine which of these services are internet-facing versus internal to prioritize your work. Coordinate with your platform or infrastructure teams to plan for necessary kernel updates, as this issue requires a software patch to the kernel itself.

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.