{"id":"CVE-2026-68178","state":"PUBLISHED","title":"misc: nsm: pin the module while the device is open","description":"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.","publishedAt":"2026-08-10T11:59:49.344Z","updatedAt":"2026-10-19T20:58:55.830Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"1996639f824ce9468395cdb7bcb8f467fa787e77","versionType":"git"},{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"1da310b94504d42001e9c32c43c5dc105b777e5f","versionType":"git"},{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"9e9a82d00c3d10129fc310a7547b24a679d5d920","versionType":"git"},{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"3b231f1e9990f4c21220d0a69733ce2105891ff9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/misc/nsm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/misc/nsm.c"]}],"references":["https://git.kernel.org/stable/c/1996639f824ce9468395cdb7bcb8f467fa787e77","https://git.kernel.org/stable/c/1da310b94504d42001e9c32c43c5dc105b777e5f","https://git.kernel.org/stable/c/9e9a82d00c3d10129fc310a7547b24a679d5d920","https://git.kernel.org/stable/c/3b231f1e9990f4c21220d0a69733ce2105891ff9"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68178.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68178","state":"PUBLISHED","datePublished":"2026-08-10T11:59:49.344Z","dateUpdated":"2026-10-19T20:58:55.830Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-30T09:28:09.373Z"},"containers":{"cna":{"title":"misc: nsm: pin the module while the device is open","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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"1996639f824ce9468395cdb7bcb8f467fa787e77","versionType":"git"},{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"1da310b94504d42001e9c32c43c5dc105b777e5f","versionType":"git"},{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"9e9a82d00c3d10129fc310a7547b24a679d5d920","versionType":"git"},{"version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","status":"affected","lessThan":"3b231f1e9990f4c21220d0a69733ce2105891ff9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/misc/nsm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/misc/nsm.c"]}],"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"}],"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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:00:19.564Z"},"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-68178","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:45:28.962889Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:58:55.830Z"}}]}}}