GHSA-Q4PW-HXG7-R6V7
Vulnerability from github – Published: 2026-09-24 18:31 – Updated: 2026-09-24 18:31In the Linux kernel, the following vulnerability has been resolved:
s390/vfio-ap: fix potential use of uninitialized apm_filtered bitmap
The DECLARE_BITMAP(apm_filtered, AP_DEVICES) macro allocates the bitmap on the stack without zero-initializing it.
In vfio_ap_mdev_hot_plug_cfg(), the vfio_ap_mdev_filter_matrix() function is only called to initialize and populate apm_filtered if either filter_adapters or filter_domains is true. If the hot plug configuration change only adds control domains (meaning filter_cdoms is true, but filter_adapters and filter_domains are both false), vfio_ap_mdev_filter_matrix() is bypassed.
Consequently, apm_filtered is passed to reset_queues_for_apids() with uninitialized stack garbage. This can cause reset_queues_for_apids() to interpret arbitrary stack garbage bits as valid APIDs to reset, potentially performing unintended guest hardware queue resets.
Fix this by zero-initializing the apm_filtered bitmap at the beginning of vfio_ap_mdev_hot_plug_cfg() using bitmap_zero().
{
"affected": [],
"aliases": [
"CVE-2026-93238"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-24T16:17:19Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio-ap: fix potential use of uninitialized apm_filtered bitmap\n\nThe DECLARE_BITMAP(apm_filtered, AP_DEVICES) macro allocates the bitmap\non the stack without zero-initializing it.\n\nIn vfio_ap_mdev_hot_plug_cfg(), the vfio_ap_mdev_filter_matrix() function\nis only called to initialize and populate apm_filtered if either\nfilter_adapters or filter_domains is true. If the hot plug configuration\nchange only adds control domains (meaning filter_cdoms is true, but\nfilter_adapters and filter_domains are both false),\nvfio_ap_mdev_filter_matrix() is bypassed.\n\nConsequently, apm_filtered is passed to reset_queues_for_apids() with\nuninitialized stack garbage. This can cause reset_queues_for_apids() to\ninterpret arbitrary stack garbage bits as valid APIDs to reset, potentially\nperforming unintended guest hardware queue resets.\n\nFix this by zero-initializing the apm_filtered bitmap at the beginning of\nvfio_ap_mdev_hot_plug_cfg() using bitmap_zero().",
"id": "GHSA-q4pw-hxg7-r6v7",
"modified": "2026-09-24T18:31:23Z",
"published": "2026-09-24T18:31:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93238"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/09548edc6114f1eb1035b30795e893204ef45b85"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4ba8a08f5f26ed59f356a6318bca3aa7cc0af3e2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6d554f2571e6b4db242593ba561efd6a6d1f99a9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bf09b9d7cd7890bc3a3b7eb63d5ece15f88bfde7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f73db632524320d2b93bc8534be8ea875053502d"
}
],
"schema_version": "1.4.0",
"severity": []
}
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