External risk intelligence

Linux Kernel SCTP Use-after-Free Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-52924

This vulnerability exists in the Linux kernel SCTP implementation. While SCTP is a network protocol, it is typically used for specific internal service communication or telecom infrastructure rather than general-purpose public-facing web traffic. Exposure depends entirely on whether an application specifically utilizes SCTP and exposes those endpoints to the public internet.

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 has been resolved in the Linux kernel's SCTP component that could lead to system instability or crashes. This issue arises from how the kernel handles specific network connection states, potentially causing memory errors if not properly managed. The main concern is to confirm if your environment utilizes this specific kernel component.

Memory error in Linux kernel network handling.
Potential for system crashes or instability.
Confirm relevance and exposure of SCTP usage.

Attack Path

How an attacker could exploit the issue

An attacker can exploit this vulnerability by sending a specially crafted network packet that triggers a rollback in the SCTP association setup. This rollback leads to a state where the system attempts to use memory that has already been freed, potentially causing a crash.

Network access required to send packets.
Stale COOKIE-ECHO handling triggers vulnerability.
Leads to system instability and crashes.

Live Threat

Current exploitation, exposure, and threat context

A use-after-free vulnerability in the Linux kernel's SCTP implementation could lead to system instability. This occurs when handling a specific error condition during association setup, potentially causing crashes when trying to process queued data.

System stability and availability.
Crashes due to invalid memory access.
Service interruptions and system reboots.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability resides in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. Ownership will likely fall to the platform or infrastructure teams responsible for the kernel and its associated services. The immediate first step is to determine if SCTP is actively used within the environment, identify any critical applications that depend on it, and then confirm the accountable owner for remediation planning.

Platform/infrastructure teams own the fix.
Verify SCTP usage and critical services.
Plan remediation based on identified risk.

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 and receive streams of data over a network, often used in specialized fields like telecommunications or specific internal service architectures. It provides reliable, ordered delivery of messages, similar to TCP but with features that support multi-homing and multi-streaming.

What does CVE-2026-52924 mean technically?

This vulnerability is a use-after-free weakness. It occurs when the kernel attempts to access memory that it has already released. In this specific case, when an SCTP connection attempt fails and rolls back, the system improperly retains a reference to old memory locations while setting up a new connection state. This mismatch causes the kernel to access invalid memory, which typically results in a system crash or service instability.

How is this vulnerability triggered?

The issue is triggered when a 'Stale Cookie' error is received during an SCTP association setup. This forces the connection state to roll back. If user data was already queued for transmission, the kernel fails to properly clear the old state. It is not triggered by standard, successful connections; it requires this specific, abnormal error-handling sequence where queued data exists during a connection rollback.

Is my system at risk?

According to Halo Surface Signal, risk depends on whether your applications specifically use SCTP and expose those endpoints to the internet. Because SCTP is typically used for internal services or telecom infrastructure rather than general web traffic, your exposure is limited to systems configured to handle SCTP connections from external sources.

What should I do to address this issue?

First, verify if your environment or specific applications actively utilize SCTP. If SCTP is in use, work with your platform or infrastructure teams to identify critical services that depend on it. Since this is a kernel-level issue, remediation will involve updating the Linux kernel to a patched version that correctly manages the outbound queue during connection rollbacks.

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.