CVE-2026-64004 Details
Description
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix locking in .getsockopt Mirror iucv_sock_setsockopt() and wrap the whole switch in lock_sock()/release_sock(). The pre-existing SO_MSGLIMIT-only lock becomes redundant and is removed. Any AF_IUCV HIPER user can potentially crash the kernel by racing recvmsg() with getsockopt(SO_MSGSIZE): the SO_MSGSIZE arm dereferences iucv->hs_dev->mtu after iucv_sock_close() (called from the racing recvmsg()) has set hs_dev to NULL, producing a NULL pointer dereference oops.
A vulnerability in the Linux kernel's handling of socket options for AF_IUCV can lead to a NULL pointer dereference, causing a kernel crash. This issue arises in versions of the Linux kernel prior to the patch included in this CVE. The vulnerability is triggered by a race condition between the recvmsg() function and the getsockopt() function when retrieving the SO_MSGSIZE option. The problem occurs because the SO_MSGSIZE handling dereferences a device MTU value that has been invalidated by a prior operation, leading to a NULL pointer dereference and a kernel oops.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been patched. Instructions for downloading the patched version can be found in the Linux kernel documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
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Weakness Enumeration
No weakness enumeration is available for this CVE.
Affected Products
No affected product data is available for this CVE.
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 20, 2026 | CVE Modified | kernel.org |
| Jul 19, 2026 | New CVE Received | kernel.org |