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Advisory severityMedium5.5Red Hat Linux

Medium [CVE-2026-64004] fix locking in.getsockopt

This medium-severity Red Hat Linux advisory covers CVE-2026-64004 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-64004 Source published Source updated

VulniPulse record published Record updated

CVE-2026-64004
Affected products & platforms
Red Hat LinuxLinux Kernel
Open source advisory

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Summary

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 flaw was found in the Linux kernel's AF_IUCV (Inter-User Communication Vehicle) networking module. A local user can exploit a race condition between message reception and socket option retrieval, specifically when calling getsockopt(SO_MSGSIZE).

This can lead to a null pointer dereference, causing the kernel to crash and resulting in a Denial of Service (DoS). Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

Weakness: CWE-476. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.

Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE.

Affected products named by the advisory: Red Hat package: kernel-rt.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · medium-confidence parse· fetched 7 days ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.

Official advisory · medium-confidence parse· fetched 7 days ago·verify at source

Mitigation

The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.

Official advisory · medium-confidence parse· fetched 7 days ago·verify at source

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