{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68178", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.373Z", "datePublished": "2026-08-10T11:59:49.344Z", "dateUpdated": "2026-08-17T05:00:19.564Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:00:19.564Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmisc: nsm: pin the module while the device is open\n\nmisc_open() installs a misc driver's file operations with fops_get(),\nwhich pins file_operations::owner before replacing the file's f_op. The\nNSM misc device leaves nsm_dev_fops.owner unset, so opening /dev/nsm does\nnot take a module reference on the nsm driver.\n\nIf the driver is built as a module, an open file descriptor can therefore\nsurvive rmmod of the module that provides its ioctl callbacks. A later\nioctl through that descriptor can call into unloaded module text.\n\nSet nsm_dev_fops.owner to THIS_MODULE so the misc core holds the module\nwhile any /dev/nsm file descriptor is open, matching the lifetime\nexpectation for the installed file operations." } ], "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 bug is reached only via local open()/ioctl syscalls on /dev/nsm (misc_open through vfs_ioctl to nsm_dev_ioctl); the Nitro Secure Module virtio driver has no network, adjacent-wireless, or physical attack surface.\nAC:L - When CONFIG_NSM=m the attacker controls the full sequence: open /dev/nsm to install fops, delete_module(\"nsm\") while fops_get(NULL) leaves the module unpinned, then ioctl on the stale fd to call unloaded text without races or external timing.\nPR:L - /dev/nsm is registered mode 0666 with no capable() checks in nsm_dev_ioctl, so any local process can open and ioctl; unloading the module needs CAP_SYS_MODULE, treated as low-privilege local capability per similar module-lifetime UAF scoring on permissive/user-namespace kernels.\nUI:N - The attacker performs open, module removal, and stale-fd ioctl from their own process; no separate victim must mount a filesystem, click a link, or take any action beyond the attacker's own operations.\nS:U - The use-after-free corrupts guest kernel memory and executes in kernel context within the Nitro Enclave; impact does not cross hypervisor, parent-instance, VM, or IOMMU security boundaries.\nC:H - Stale ioctl calls into freed module text and file_to_nsm() dereferences freed devm nsm state, exposing reclaimed kernel/module memory and adjacent virtio message buffers through the UAF window.\nI:H - Dispatching nsm_dev_ioctl through freed vmalloc module text is a kernel use-after-free that can be shaped with heap spraying to hijack control flow and achieve arbitrary kernel code execution.\nA:H - Executing code from an unloaded module or dereferencing freed nsm/virtqueue state on ioctl reliably causes kernel oops or panic, and the attacker can repeat the stale-fd ioctl to deny service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/misc/nsm.c" ], "versions": [ { "version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749", "lessThan": "1996639f824ce9468395cdb7bcb8f467fa787e77", "status": "affected", "versionType": "git" }, { "version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749", "lessThan": "1da310b94504d42001e9c32c43c5dc105b777e5f", "status": "affected", "versionType": "git" }, { "version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749", "lessThan": "9e9a82d00c3d10129fc310a7547b24a679d5d920", "status": "affected", "versionType": "git" }, { "version": "b9873755a6c8ccfce79094c4dce9efa3ecb1a749", "lessThan": "3b231f1e9990f4c21220d0a69733ce2105891ff9", "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/misc/nsm.c" ], "versions": [ { "version": "6.8", "status": "affected" }, { "version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "6.8", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/1996639f824ce9468395cdb7bcb8f467fa787e77" }, { "url": "https://git.kernel.org/stable/c/1da310b94504d42001e9c32c43c5dc105b777e5f" }, { "url": "https://git.kernel.org/stable/c/9e9a82d00c3d10129fc310a7547b24a679d5d920" }, { "url": "https://git.kernel.org/stable/c/3b231f1e9990f4c21220d0a69733ce2105891ff9" } ], "title": "misc: nsm: pin the module while the device is open", "x_generator": { "engine": "bippy-1.2.0" } } } }