{"id":"CVE-2026-89955","published":"2026-09-16T11:17:05.797","lastModified":"2026-09-16T11:17:05.797","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio-ap: Fix NULL deref in status_show() during queue probe\n\nWhen vfio_ap_mdev_probe_queue() creates the sysfs attribute group,\nthe queue's driver data has not yet been set. A concurrent read of\nthe 'status' attribute can therefore call dev_get_drvdata() and\nget NULL, which is then passed directly to\nvfio_ap_mdev_for_queue() where q->apqn is unconditionally\ndereferenced, causing a NULL pointer dereference.\n\nFix this by acquiring the update locks before calling\nsysfs_create_group(). The status_show() function acquires\nguests_lock before reading the driver data, so any concurrent\nread will block until after dev_set_drvdata() has been called\nand the update locks are released.\n\nAs a bonus, the APQN no longer needs to be read from the queue\nstruct after allocation — it can be read directly from apdev\nbefore allocation and stored in a local variable, which is then\nassigned to q->apqn once the allocation succeeds.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/31fa0a8a3c337ed2d200166d6926ab23c14f8b2e","tags":[]},{"url":"https://git.kernel.org/stable/c/69632952aca04caa71e49953b6949fc04e788e67","tags":[]},{"url":"https://git.kernel.org/stable/c/7db2511fc601ca3a6e3fb1bdce02261c3c3167c3","tags":[]},{"url":"https://git.kernel.org/stable/c/dd6f4ef6f8a37412909ad787c837332fb070159c","tags":[]},{"url":"https://git.kernel.org/stable/c/e102ce0f4af99dff769a4b1b4daa4cc6bd5ad2d9","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}