CVE-2026-89956

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89956", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.778Z", "datePublished": "2026-09-16T10:32:39.847Z", "dateUpdated": "2026-10-30T12:33:34.479Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:33:34.479Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio-ap: Fix missing lock required to access list of ap_matrix_mdev objects\n\nIn order to traverse or add/remove ap_matrix_mdev objects in the\nmatrix_dev->mdev_list, the matrix_dev->guests_lock mutex must be held.\nThere are two functions that access the list without holding the mutex:\n\nvfio_ap_mdev_probe function\n~~~~~~~~~~~~~~~~~~~~~~~~~~~\nThe vfio_ap_mdev_probe function uses the matrix_dev->mdevs_lock\nmutex to guard the add of a newly created ap_matrix_mdev object to the\nmatrix_dev->mdev_list. This mutex does not protect list access; its purpose\nis to guard against concurrent access to fields contained in an\nap_matrix_mdev object. This could lead to kernel memory corruption or\nuse-after-free if another mdev is created or removed concurrently.\n\nThe adding of an ap_matrix_mdev object to matrix_dev->mdev_list\nis now guarded by the matrix_dev->guests_lock which is the correct\nway to protect against concurrent mdev_list access.\n\nAlso removed the following two lines of code because the matrix_mdev is\nallocated via vfio_alloc_device macro which uses kzalloc, so req_trigger\nand cfg_chg_trigger are already zero-initialised when the struct is\nallocated before the call to vfio_register_emulated_iommu_dev. This\nprevents a window whereby these triggers are set to NULL after\nthe device is exposed to userspace.\n\nmatrix_mdev->req_trigger = NULL;\nmatrix_mdev->cfg_chg_trigger = NULL;\n\nvfio_ap_mdev_for_queue function\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\nThe status_show function that supports display of the status attribute of\nthe devices in /sys/bus/ap/devices calls the vfio_ap_mdev_for_queue\nfunction which iterates the matrix_dev->mdev_list to find the object\nrepresenting the queue device whose status is to be displayed. In order to\ntraverse this list, the matrix_dev->guests_lock mutex must be held.\n\nTo fix this, the guests_lock mutex is taken prior to taking the\nmatrix_dev->mdevs_lock mutex in the status_show function. It is taken\nthere rather than the vfio_ap_mdev_for_queue function - where it is\nneeded - because it must be taken prior to the mdevs_lock mutex in order to\nadhere to the proper locking order and prevent a lockdep splat; also\nbecause the mdevs_lock is needed there to access fields within\nthe matrix_mdev object in that function.\n\nSee the vfio-ap-locking.rst in the linux kernel tree."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/s390/crypto/vfio_ap_ops.c"], "versions": [{"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "lessThan": "3ea443510739468238324234eaab0d37922283f5", "status": "affected", "versionType": "git"}, {"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "lessThan": "22dc712c170efc1a549e3f872467c880be995ac7", "status": "affected", "versionType": "git"}, {"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "lessThan": "530ee1cc71562b6799b9ece187b6c1b757a2c6fa", "status": "affected", "versionType": "git"}, {"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "lessThan": "647916988272fe5ecb4bb30cd02b51af9960618a", "status": "affected", "versionType": "git"}, {"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "lessThan": "0fd74477d05743d4cd9b25a3b667daa278d53b93", "status": "affected", "versionType": "git"}, {"version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "lessThan": "7fa61c29850d05e40ca9ed41bfdf57673023f581", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/s390/crypto/vfio_ap_ops.c"], "versions": [{"version": "6.0", "status": "affected"}, {"version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.12.112"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.18.51"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.2.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/3ea443510739468238324234eaab0d37922283f5"}, {"url": "https://git.kernel.org/stable/c/22dc712c170efc1a549e3f872467c880be995ac7"}, {"url": "https://git.kernel.org/stable/c/530ee1cc71562b6799b9ece187b6c1b757a2c6fa"}, {"url": "https://git.kernel.org/stable/c/647916988272fe5ecb4bb30cd02b51af9960618a"}, {"url": "https://git.kernel.org/stable/c/0fd74477d05743d4cd9b25a3b667daa278d53b93"}, {"url": "https://git.kernel.org/stable/c/7fa61c29850d05e40ca9ed41bfdf57673023f581"}], "title": "s390/vfio-ap: Fix missing lock required to access list of ap_matrix_mdev objects", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/s390/crypto/vfio_ap_ops.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "3ea443510739468238324234eaab0d37922283f5", "status": "affected", "version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "versionType": "git"}, {"lessThan": "22dc712c170efc1a549e3f872467c880be995ac7", "status": "affected", "version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "versionType": "git"}, {"lessThan": "530ee1cc71562b6799b9ece187b6c1b757a2c6fa", "status": "affected", "version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "versionType": "git"}, {"lessThan": "647916988272fe5ecb4bb30cd02b51af9960618a", "status": "affected", "version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "versionType": "git"}, {"lessThan": "0fd74477d05743d4cd9b25a3b667daa278d53b93", "status": "affected", "version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "versionType": "git"}, {"lessThan": "7fa61c29850d05e40ca9ed41bfdf57673023f581", "status": "affected", "version": "2c1ee8983aa377fef4f725162f4f3aa5f9575d4a", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/s390/crypto/vfio_ap_ops.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.0"}, {"lessThan": "6.0", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.160", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.112", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.51", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.5", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio-ap: Fix missing lock required to access list of ap_matrix_mdev objects\n\nIn order to traverse or add/remove ap_matrix_mdev objects in the\nmatrix_dev->mdev_list, the matrix_dev->guests_lock mutex must be held.\nThere are two functions that access the list without holding the mutex:\n\nvfio_ap_mdev_probe function\n~~~~~~~~~~~~~~~~~~~~~~~~~~~\nThe vfio_ap_mdev_probe function uses the matrix_dev->mdevs_lock\nmutex to guard the add of a newly created ap_matrix_mdev object to the\nmatrix_dev->mdev_list. This mutex does not protect list access; its purpose\nis to guard against concurrent access to fields contained in an\nap_matrix_mdev object. This could lead to kernel memory corruption or\nuse-after-free if another mdev is created or removed concurrently.\n\nThe adding of an ap_matrix_mdev object to matrix_dev->mdev_list\nis now guarded by the matrix_dev->guests_lock which is the correct\nway to protect against concurrent mdev_list access.\n\nAlso removed the following two lines of code because the matrix_mdev is\nallocated via vfio_alloc_device macro which uses kzalloc, so req_trigger\nand cfg_chg_trigger are already zero-initialised when the struct is\nallocated before the call to vfio_register_emulated_iommu_dev. This\nprevents a window whereby these triggers are set to NULL after\nthe device is exposed to userspace.\n\nmatrix_mdev->req_trigger = NULL;\nmatrix_mdev->cfg_chg_trigger = NULL;\n\nvfio_ap_mdev_for_queue function\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\nThe status_show function that supports display of the status attribute of\nthe devices in /sys/bus/ap/devices calls the vfio_ap_mdev_for_queue\nfunction which iterates the matrix_dev->mdev_list to find the object\nrepresenting the queue device whose status is to be displayed. In order to\ntraverse this list, the matrix_dev->guests_lock mutex must be held.\n\nTo fix this, the guests_lock mutex is taken prior to taking the\nmatrix_dev->mdevs_lock mutex in the status_show function. It is taken\nthere rather than the vfio_ap_mdev_for_queue function - where it is\nneeded - because it must be taken prior to the mdevs_lock mutex in order to\nadhere to the proper locking order and prevent a lockdep splat; also\nbecause the mdevs_lock is needed there to access fields within\nthe matrix_mdev object in that function.\n\nSee the vfio-ap-locking.rst in the linux kernel tree."}], "id": "CVE-2026-89956", "lastModified": "2026-10-30T13:20:36.793", "metrics": {}, "published": "2026-09-16T11:17:05.920", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0fd74477d05743d4cd9b25a3b667daa278d53b93"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/22dc712c170efc1a549e3f872467c880be995ac7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3ea443510739468238324234eaab0d37922283f5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/530ee1cc71562b6799b9ece187b6c1b757a2c6fa"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/647916988272fe5ecb4bb30cd02b51af9960618a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7fa61c29850d05e40ca9ed41bfdf57673023f581"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2c1ee8983aa377fef4f725162f4f3aa5f9575d4a,647916988272fe5ecb4bb30cd02b51af9960618a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2c1ee8983aa377fef4f725162f4f3aa5f9575d4a,0fd74477d05743d4cd9b25a3b667daa278d53b93)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2c1ee8983aa377fef4f725162f4f3aa5f9575d4a,7fa61c29850d05e40ca9ed41bfdf57673023f581)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.51,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.5,7.2.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-17T13:15:12.758654+00:00", "updated": "2026-09-18T07:30:05.849596+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-666", "CWE-416"]}