{"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":"2026-09-14T12:02:25.695Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-14T12:02:25.695Z"},"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-rc1","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-rc1"}]}]}],"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"}}}}