{"api_version":"1","generated_at":"2026-08-21T01:03:27+00:00","cve":"CVE-2026-68179","urls":{"html":"https://cve.report/CVE-2026-68179","api":"https://cve.report/api/cve/CVE-2026-68179.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-68179","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-68179"},"summary":{"title":"misc: nsm: only unlock nsm_dev on post-lock error paths","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmisc: nsm: only unlock nsm_dev on post-lock error paths\n\nnsm_dev_ioctl() jumps to the common out label even when the initial\ncopy_from_user() fails before nsm->lock has been taken.  The error path\nthen blindly unlocks a mutex that was never acquired.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the miscdevice ioctl entry and the pre-lock\ncopy_from_user(&raw, argp, _IOC_SIZE(cmd)) failure path by issuing\nNSM_IOCTL_RAW with an invalid user pointer.  That failure reaches the\nshared out label before mutex_lock(&nsm->lock).  Lockdep reported:\n\n  WARNING: bad unlock balance detected!\n  exploit/193 is trying to release lock (&global_nsm.lock) at:\n  nsm_dev_ioctl+0x5f/0xcf [vuln_msv]\n  but there are no more locks to release!\n  no locks held by exploit/193.\n\nReturn immediately on the pre-lock copy_from_user() failure and keep the\ncommon unlock label for the post-lock paths only.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-10 13:20:04","updated_at":"2026-08-17 05:18:19"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.4","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.4,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.4","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":8.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/ce1fed11d18e163baf7f875152a33bf80f625c1a","name":"https://git.kernel.org/stable/c/ce1fed11d18e163baf7f875152a33bf80f625c1a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8f068342096b027181b168d91fef7ac7a2c64b25","name":"https://git.kernel.org/stable/c/8f068342096b027181b168d91fef7ac7a2c64b25","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb","name":"https://git.kernel.org/stable/c/4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f318f5a872cb9096536e759b23ae5c9873bb80ed","name":"https://git.kernel.org/stable/c/f318f5a872cb9096536e759b23ae5c9873bb80ed","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-68179","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68179","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b9873755a6c8ccfce79094c4dce9efa3ecb1a749 4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b9873755a6c8ccfce79094c4dce9efa3ecb1a749 8f068342096b027181b168d91fef7ac7a2c64b25 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b9873755a6c8ccfce79094c4dce9efa3ecb1a749 f318f5a872cb9096536e759b23ae5c9873bb80ed git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b9873755a6c8ccfce79094c4dce9efa3ecb1a749 ce1fed11d18e163baf7f875152a33bf80f625c1a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.8","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.8 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.101 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.42 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.6 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"68179","cve":"CVE-2026-68179","epss":"0.001820000","percentile":"0.081060000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:47"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/misc/nsm.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb","status":"affected","version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","versionType":"git"},{"lessThan":"8f068342096b027181b168d91fef7ac7a2c64b25","status":"affected","version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","versionType":"git"},{"lessThan":"f318f5a872cb9096536e759b23ae5c9873bb80ed","status":"affected","version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","versionType":"git"},{"lessThan":"ce1fed11d18e163baf7f875152a33bf80f625c1a","status":"affected","version":"b9873755a6c8ccfce79094c4dce9efa3ecb1a749","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/misc/nsm.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.8"},{"lessThan":"6.8","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.101","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.42","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.101","versionStartIncluding":"6.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.42","versionStartIncluding":"6.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.6","versionStartIncluding":"6.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.8","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmisc: nsm: only unlock nsm_dev on post-lock error paths\n\nnsm_dev_ioctl() jumps to the common out label even when the initial\ncopy_from_user() fails before nsm->lock has been taken.  The error path\nthen blindly unlocks a mutex that was never acquired.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the miscdevice ioctl entry and the pre-lock\ncopy_from_user(&raw, argp, _IOC_SIZE(cmd)) failure path by issuing\nNSM_IOCTL_RAW with an invalid user pointer.  That failure reaches the\nshared out label before mutex_lock(&nsm->lock).  Lockdep reported:\n\n  WARNING: bad unlock balance detected!\n  exploit/193 is trying to release lock (&global_nsm.lock) at:\n  nsm_dev_ioctl+0x5f/0xcf [vuln_msv]\n  but there are no more locks to release!\n  no locks held by exploit/193.\n\nReturn immediately on the pre-lock copy_from_user() failure and keep the\ncommon unlock label for the post-lock paths only."}],"metrics":[{"cvssV3_1":{"baseScore":8.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The flaw is reached only via the local ioctl syscall on /dev/nsm (open plus ioctl through vfs_ioctl to nsm_dev_ioctl); it is not exposed through any network protocol or remote service.\nAC:L - An attacker can reliably trigger the pre-lock copy_from_user failure with an invalid userspace pointer and can control the race by issuing concurrent ioctl or /dev/hwrng reads against the same nsm->lock.\nPR:N - The driver registers /dev/nsm as mode 0666 and performs no capability or permission checks in nsm_dev_ioctl, so any local process can open the device and issue NSM_IOCTL_RAW without elevated privileges.\nUI:N - Exploitation requires only the attacker issuing a crafted ioctl with an invalid argument pointer; no victim interaction, mounting, or other user action is needed.\nS:U - Impact is confined to corruption and privilege within the guest Nitro Enclave kernel; it does not cross into the hypervisor, parent instance, or another VM security boundary.\nC:H - Unlocking a mutex not held by the caller can clear owner while another context still holds nsm->lock, permitting concurrent unsynchronized access to shared nsm_msg buffers and virtio response data.\nI:H - Premature mutex release enables overlapping virtqueue operations and corruption of shared kernel message state, a memory-safety defect that can be leveraged for arbitrary kernel integrity compromise.\nA:H - The bug triggers lockdep bad-unlock warnings and kernel oops, and concurrent unsynchronized virtio access can panic, hang, or otherwise deny service to the enclave."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:00:20.666Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fb"},{"url":"https://git.kernel.org/stable/c/8f068342096b027181b168d91fef7ac7a2c64b25"},{"url":"https://git.kernel.org/stable/c/f318f5a872cb9096536e759b23ae5c9873bb80ed"},{"url":"https://git.kernel.org/stable/c/ce1fed11d18e163baf7f875152a33bf80f625c1a"}],"title":"misc: nsm: only unlock nsm_dev on post-lock error paths","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-68179","datePublished":"2026-08-10T11:59:50.667Z","dateReserved":"2026-07-30T09:28:09.373Z","dateUpdated":"2026-08-17T05:00:20.666Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-10 13:20:04","lastModifiedDate":"2026-08-17 05:18:19","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.4,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.5,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"68179","Ordinal":"1","Title":"misc: nsm: only unlock nsm_dev on post-lock error paths","CVE":"CVE-2026-68179","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"68179","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmisc: nsm: only unlock nsm_dev on post-lock error paths\n\nnsm_dev_ioctl() jumps to the common out label even when the initial\ncopy_from_user() fails before nsm->lock has been taken.  The error path\nthen blindly unlocks a mutex that was never acquired.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the miscdevice ioctl entry and the pre-lock\ncopy_from_user(&raw, argp, _IOC_SIZE(cmd)) failure path by issuing\nNSM_IOCTL_RAW with an invalid user pointer.  That failure reaches the\nshared out label before mutex_lock(&nsm->lock).  Lockdep reported:\n\n  WARNING: bad unlock balance detected!\n  exploit/193 is trying to release lock (&global_nsm.lock) at:\n  nsm_dev_ioctl+0x5f/0xcf [vuln_msv]\n  but there are no more locks to release!\n  no locks held by exploit/193.\n\nReturn immediately on the pre-lock copy_from_user() failure and keep the\ncommon unlock label for the post-lock paths only.","Type":"Description","Title":"misc: nsm: only unlock nsm_dev on post-lock error paths"}]}}}