CVE-2026-53325

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.

• linux linux kernel (>= 2.6.18 < 5.10.260) • linux linux kernel (>= 5.11 < 5.15.211) • linux linux kernel (>= 5.16 < 6.1.177) • linux linux kernel (>= 6.2 < 6.6.144) • linux linux kernel (>= 6.7 < 6.12.95) • linux linux kernel (>= 6.13 < 6.18.37) • linux linux kernel (>= 6.19 < 7.0.14) • linux linux kernel (>= 7.1 < 7.1.2)