CVE-2026-68397
Received Received - Intake

Memory Corruption in Linux Kernel IUCV Socket Handling

Publication date: 2026-08-10

Last updated on: 2026-08-10

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
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-68397
EUVD
EUVD-2026-55583

Affected Vendors & Products

Currently, no data is known.

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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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.

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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