s390/vfio-ap: Fix missing lock required to access list of ap_matrix_mdev objects
In the Linux kernel, the following vulnerability has been resolved: s390/vfio-ap: Fix missing lock required to access list of ap_matrix_mdev objects In order to traverse or add/remove ap_matrix_mdev objects in the matrix_dev->mdev_list, the matrix_dev->guests_lock mutex must be held. There are two functions that access the list without holding the mutex: vfio_ap_mdev_probe function ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The vfio_ap_mdev_probe function uses the matrix_dev->mdevs_lock mutex to guard the add of a newly created ap_matrix_mdev object to the matrix_dev->mdev_list. This mutex does not protect list access; its purpose is to guard against concurrent access to fields contained in an ap_matrix_mdev object. This could lead to kernel memory corruption or use-after-free if another mdev is created or removed concurrently. The adding of an ap_matrix_mdev object to matrix_dev->mdev_list is now guarded by the matrix_dev->guests_lock which is the correct way to protect against concurrent mdev_list access. Also removed the following two lines of code because the matrix_mdev is allocated via vfio_alloc_device macro which uses kzalloc, so req_trigger and cfg_chg_trigger are already zero-initialised when the struct is allocated before the call to vfio_register_emulated_iommu_dev. This prevents a window whereby these triggers are set to NULL after the device is exposed to userspace. matrix_mdev->req_trigger = NULL; matrix_mdev->cfg_chg_trigger = NULL; vfio_ap_mdev_for_queue function ~~~~~~~~~~
CVE-2026-89956
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89956
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a",
"lessThan": "22dc712c170efc1a549e3f872467c880be995ac7",
"versionType": "git"
},
{
"status": "affected",
"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a",
"lessThan": "530ee1cc71562b6799b9ece187b6c1b757a2c6fa",
"versionType": "git"
},
{
"status": "affected",
"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a",
"lessThan": "647916988272fe5ecb4bb30cd02b51af9960618a",
"versionType": "git"
},
{
"status": "affected",
"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a",
"lessThan": "0fd74477d05743d4cd9b25a3b667daa278d53b93",
"versionType": "git"
},
{
"status": "affected",
"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a",
"lessThan": "7fa61c29850d05e40ca9ed41bfdf57673023f581",
"versionType": "git"
}
],
"programFiles": [
"drivers/s390/crypto/vfio_ap_ops.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/s390/crypto/vfio_ap_ops.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89956
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #48571 · Revision 1
- Added to Heist Feed
- Publisher date