{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89742", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.761Z", "datePublished": "2026-09-11T19:46:48.522Z", "dateUpdated": "2026-10-19T08:51:56.183Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:51:56.183Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrapidio: mport_cdev: fix use-after-free in dma_req_free()\n\ndma_req_free() acquires buf_mutex through req->map, drops the mapping\nreference with kref_put(), and then dereferences req->map again to unlock\nthe mutex.\n\nIf kref_put() drops the last reference, mport_release_mapping() frees the\nmapping, and the subsequent mutex_unlock() dereferences a freed object. \nThis is a use-after-free.\n\nFix this by caching map and md before kref_put(), clearing req->map while\nholding buf_mutex, and using the cached md for mutex unlocking.\n\nThe bug is reachable from userspace via the RapidIO mport character device\ninterface." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The use-after-free is reached only through local ioctls on /dev/rio_mportN (RIO_ALLOC_DMA, RIO_TRANSFER with a kernel DMA handle, RIO_FREE_DMA, then close or RIO_WAIT_FOR_ASYNC). RapidIO is a board-level fabric, and this dma_req_free() path is not driven by received packets.\nAC:L - An attacker who can open the mport node deterministically allocates a DMA mapping, submits an async RIO_TRANSFER that takes a kref on it, drops the owner ref with RIO_FREE_DMA, then frees the request so dma_req_free() performs the last kref_put(); no condition outside the attacker’s control is required.\nPR:L - mport_cdev_open() and the DMA ioctls perform no capable() checks; access is gated only by /dev/rio_mportN permissions, and RapidIO deployments commonly give fabric-management daemons group access to that node, so an unprivileged local user with the device can drive the bug.\nUI:N - Exploitation is entirely self-driven via the attacker’s own open/ioctl/close sequence on the mport character device; no separate victim action such as mounting a filesystem or opening a file is required.\nS:U - The freed rio_mport_mapping and the subsequent mutex unlock occur in kernel heap within the host OS authority; this is a standard kernel use-after-free and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - dma_req_free() dereferences req->map after mport_release_mapping() has kfree’d that kmalloc object; reclaiming the slab lets an attacker control map->md and read through the dangling pointer, a classic use-after-free disclosure primitive.\nI:H - Unlocking buf_mutex via a reclaimed map->md causes mutex_unlock() on an attacker-chosen address (fake-mutex wait_list write), so the use-after-free is exploitable for arbitrary kernel write and control-flow hijack.\nA:H - Use-after-free of rio_mport_mapping during mutex_unlock() oopses or panics under slab poisoning or init_on_free, and targeting a fake md leaves the real buf_mutex locked, deadlocking mapping paths and crashing or hanging the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/rapidio/devices/rio_mport_cdev.c" ], "versions": [ { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "00c5ed913b0dc563fbeb8a97ea8916c03bbbbf6a", "status": "affected", "versionType": "git" }, { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "fc79c07cdcde02c5b17633d78777de6ac2c14b29", "status": "affected", "versionType": "git" }, { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "26ccfe7d69e27b0d933ae0a64a23a0cb9b9a85a6", "status": "affected", "versionType": "git" }, { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "bd8881c24a9520f9c3d3e855d866197f63e471a7", "status": "affected", "versionType": "git" }, { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "9a9929ec875ff20922c90c96fd544ae8a2a61a8d", "status": "affected", "versionType": "git" }, { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0", "status": "affected", "versionType": "git" }, { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "211c68d817a3d9dc14c0026a59da7cac30f8147e", "status": "affected", "versionType": "git" }, { "version": "e8de370188d098bb49483c287b44925957c3c9b6", "lessThan": "5cbef379a94b161726c5f504598bf4791d45cedc", "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/rapidio/devices/rio_mport_cdev.c" ], "versions": [ { "version": "4.6", "status": "affected" }, { "version": "0", "lessThan": "4.6", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "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": "4.6", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.6", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/00c5ed913b0dc563fbeb8a97ea8916c03bbbbf6a" }, { "url": "https://git.kernel.org/stable/c/fc79c07cdcde02c5b17633d78777de6ac2c14b29" }, { "url": "https://git.kernel.org/stable/c/26ccfe7d69e27b0d933ae0a64a23a0cb9b9a85a6" }, { "url": "https://git.kernel.org/stable/c/bd8881c24a9520f9c3d3e855d866197f63e471a7" }, { "url": "https://git.kernel.org/stable/c/9a9929ec875ff20922c90c96fd544ae8a2a61a8d" }, { "url": "https://git.kernel.org/stable/c/e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0" }, { "url": "https://git.kernel.org/stable/c/211c68d817a3d9dc14c0026a59da7cac30f8147e" }, { "url": "https://git.kernel.org/stable/c/5cbef379a94b161726c5f504598bf4791d45cedc" } ], "title": "rapidio: mport_cdev: fix use-after-free in dma_req_free()", "x_generator": { "engine": "bippy-1.2.0" } } } }