CVE-2026-68397

Received Received - Intake

Memory Corruption in Linux Kernel IUCV Socket Handling

Publication date: 2026-08-10

Last updated on: 2026-10-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net/iucv: take a reference on the socket found in afiucv_hs_rcv() afiucv_hs_rcv() looks up the destination socket under iucv_sk_list.lock, drops the lock, and then passes the socket to the afiucv_hs_callback_*() handlers without holding a reference. AF_IUCV sockets are not RCU-protected and are freed synchronously by iucv_sock_kill() -> sock_put(), so a concurrent close can free the socket in the window between read_unlock() and the handler, which then dereferences freed memory (for example sk->sk_data_ready() in afiucv_hs_callback_syn()). Take a reference with sock_hold() while the socket is still on the list and release it with sock_put() once the handler has run.

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Meta Information

Published

2026-08-10

Last Modified

2026-10-19

Generated

2026-11-08

AI Q&A

2026-08-10

EPSS Evaluated

2026-11-07

NVD

CVE-2026-68397

EUVD

EUVD-2026-55583

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This is a use-after-free vulnerability in the Linux kernel's AF_IUCV (Inter-User Communication Vehicle) socket implementation. The issue occurs in afiucv_hs_rcv() where a socket is looked up under a lock, the lock is released, and then the socket is passed to a callback handler without holding a reference. If the socket is closed concurrently, it can be freed before the handler runs, causing the handler to dereference freed memory.

Detection Guidance

This vulnerability affects the Linux kernel's AF_IUCV socket handling. Detection requires checking kernel versions and examining kernel logs for related crashes or memory corruption events. Commands like 'uname -a' to check kernel version and 'dmesg | grep iucv' to inspect kernel logs may help identify affected systems.

Impact Analysis

This vulnerability could allow an attacker to cause a denial-of-service (system crash) or potentially execute arbitrary code with kernel privileges. It affects systems using AF_IUCV sockets, which are primarily used for communication between z/VM guests on IBM Z systems.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a memory safety issue in the Linux kernel's AF_IUCV socket handling that could lead to use-after-free errors. Compliance impacts would only occur if exploitation led to unauthorized data access or system compromise, which is not specified in the provided context.

Mitigation Strategies

Apply the latest kernel patches or updates that address this issue. If immediate patching is not possible, consider disabling AF_IUCV sockets if not required, or restrict network access to systems using this protocol to reduce exposure.

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