Copyright © 2012 Red Hat, Inc. All rights reserved. Low 2026-06-29T00:00:00 kernel: agp/amd64: Fix broken error propagation in agp_amd64_probe() 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-476

In the Linux kernel, the following vulnerability has been resolved: agp/amd64: Fix broken error propagation in agp_amd64_probe() A NULL pointer dereference was observed in the AMD64 AGP driver when running in a virtualized environment (e.g. qemu/kvm) without a physical AMD northbridge. The crash occurs in amd64_fetch_size() when attempting to dereference the pointer returned by node_to_amd_nb(0). The root cause of this crash is broken error propagation in agp_amd64_probe(): When no AMD northbridges are found, cache_nbs() correctly returns -ENODEV. However, the probe function erroneously checks the return value against exactly -1, rather than < 0. As a result, the hardware absence error is masked, allowing the driver to improperly proceed with initialization. It eventually calls agp_add_bridge(), which invokes amd64_fetch_size(). Since the hardware does not exist, node_to_amd_nb(0) returns NULL, leading to a General Protection Fault (GPF) when accessing its ->misc member. Fix the issue by correcting the error check in agp_amd64_probe() to abort properly when cache_nbs() returns any negative error code. This prevents the driver from erroneously proceeding without hardware, thereby avoiding the subsequent NULL pointer dereference at its source.

A flaw was found in the Linux kernel's AMD64 AGP (Accelerated Graphics Port) driver. This vulnerability occurs in virtualized environments lacking a physical AMD northbridge. Due to incorrect error handling, the driver attempts to initialize without the required hardware, leading to a NULL pointer dereference and causing the system to crash. This can result in a Denial of Service (DoS) for the affected system.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Fix deferred kernel Red Hat Enterprise Linux 7 Fix deferred kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-53325 https://nvd.nist.gov/vuln/detail/CVE-2026-53325 https://lore.kernel.org/linux-cve-announce/2026062926-CVE-2026-53325-b162@gregkh/T