{"api_version":"1","generated_at":"2026-08-22T10:19:01+00:00","cve":"CVE-2026-74338","urls":{"html":"https://cve.report/CVE-2026-74338","api":"https://cve.report/api/cve/CVE-2026-74338.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74338","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74338"},"summary":{"title":"bpf: Reject sleepable BPF_LSM_CGROUP programs at load time","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject sleepable BPF_LSM_CGROUP programs at load time\n\nThe cgroup shim runs under rcu_read_lock_dont_migrate(), so we should\nnot attach any sleepable BPF programs there. Add support to the verifier\nto explicitly reject attempts to load sleepable BPF programs destined\nfor LSM cgroup attachment.\n\nWithout this, we get the following splat from a BPF_LSM_CGROUP\nprogram marked BPF_F_SLEEPABLE attached to file_open when it calls\nbpf_get_dentry_xattr():\n\n  BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1567\n  in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 34317, name: load\n  preempt_count: 0, expected: 0\n  RCU nest depth: 2, expected: 0\n  Call Trace:\n   down_read+0x76/0x480\n   ext4_xattr_get+0x11f/0x700\n   __vfs_getxattr+0xf0/0x150\n   bpf_get_dentry_xattr+0xbb/0xf0\n   bpf_prog_e76a298dac9218c6_test_open+0x6a/0x85\n   __cgroup_bpf_run_lsm_current+0x326/0x840\n   bpf_trampoline_6442534646+0x62/0x14d\n   security_file_open+0x34/0x60\n   do_dentry_open+0x340/0x1260\n   vfs_open+0x7a/0x440\n   path_openat+0x1bac/0x30a0\n\nlibbpf provides a .s named section variant for every sleepable\nprogram type except lsm_cgroup, reflecting that per-cgroup LSM programs\nare intended to only run in a non-sleepable context.\n\nThe above splat was obtained by bypassing libbpf by using bpf(2)\ndirectly.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:22:34","updated_at":"2026-08-17 06:19:28"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/5b038319be442c620f774e6fc9e9283deeca1c75","name":"https://git.kernel.org/stable/c/5b038319be442c620f774e6fc9e9283deeca1c75","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/be9eaf2bb5db4ad3de61ef739fd268fd7f135737","name":"https://git.kernel.org/stable/c/be9eaf2bb5db4ad3de61ef739fd268fd7f135737","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74338","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74338","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e be9eaf2bb5db4ad3de61ef739fd268fd7f135737 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e 5b038319be442c620f774e6fc9e9283deeca1c75 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 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":"74338","cve":"CVE-2026-74338","epss":"0.001280000","percentile":"0.028420000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:46"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/bpf/verifier.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"be9eaf2bb5db4ad3de61ef739fd268fd7f135737","status":"affected","version":"69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e","versionType":"git"},{"lessThan":"5b038319be442c620f774e6fc9e9283deeca1c75","status":"affected","version":"69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/bpf/verifier.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.0"},{"lessThan":"6.0","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","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":"7.1.5","versionStartIncluding":"6.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.0","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject sleepable BPF_LSM_CGROUP programs at load time\n\nThe cgroup shim runs under rcu_read_lock_dont_migrate(), so we should\nnot attach any sleepable BPF programs there. Add support to the verifier\nto explicitly reject attempts to load sleepable BPF programs destined\nfor LSM cgroup attachment.\n\nWithout this, we get the following splat from a BPF_LSM_CGROUP\nprogram marked BPF_F_SLEEPABLE attached to file_open when it calls\nbpf_get_dentry_xattr():\n\n  BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1567\n  in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 34317, name: load\n  preempt_count: 0, expected: 0\n  RCU nest depth: 2, expected: 0\n  Call Trace:\n   down_read+0x76/0x480\n   ext4_xattr_get+0x11f/0x700\n   __vfs_getxattr+0xf0/0x150\n   bpf_get_dentry_xattr+0xbb/0xf0\n   bpf_prog_e76a298dac9218c6_test_open+0x6a/0x85\n   __cgroup_bpf_run_lsm_current+0x326/0x840\n   bpf_trampoline_6442534646+0x62/0x14d\n   security_file_open+0x34/0x60\n   do_dentry_open+0x340/0x1260\n   vfs_open+0x7a/0x440\n   path_openat+0x1bac/0x30a0\n\nlibbpf provides a .s named section variant for every sleepable\nprogram type except lsm_cgroup, reflecting that per-cgroup LSM programs\nare intended to only run in a non-sleepable context.\n\nThe above splat was obtained by bypassing libbpf by using bpf(2)\ndirectly."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires bpf(2) to load/attach a BPF_LSM_CGROUP program and a local file open to hit security_file_open; BPF/cgroup control is syscall-local, not reachable from remote network protocols.\nAC:L - On kernels with CONFIG_BPF_LSM and CONFIG_CGROUP_BPF, an attacker with BPF privileges can deterministically load BPF_F_SLEEPABLE BPF_LSM_CGROUP on file_open and trigger it with their own open(), without races or external preconditions.\nPR:L - Loading BPF_PROG_TYPE_LSM requires CAP_BPF and CAP_PERFMON, and attaching to a cgroup2 fd requires cgroup write access; both are obtainable by an unprivileged user via user namespaces (unshare -Urn) per kernel CVSS guidance.\nUI:N - No victim interaction is required; once the sleepable BPF_LSM_CGROUP program is attached, any file open in that cgroup automatically invokes the vulnerable non-sleepable cgroup LSM shim path.\nS:U - Impact stays within kernel security authority (kernel panic/hang or memory corruption from invalid-context sleeping); it is not a VM escape, IOMMU bypass, or cross-authority sandbox breakout.\nC:H - Calling sleepable helpers like bpf_get_dentry_xattr from rcu_read_lock_dont_migrate() can sleep on inode rwsems while RCU references remain, enabling use-after-free and arbitrary kernel memory disclosure beyond the intended xattr read.\nI:H - Sleeping in the cgroup BPF LSM RCU-critical section can corrupt VFS/inode lifetime and lock state, plausibly yielding arbitrary kernel write or control-flow hijack primitives, not merely a contained helper failure.\nA:H - The bug triggers \"BUG: sleeping function called from invalid context\" (demonstrated on file_open) and can also cause RCU stalls, deadlocks, oops, or kernel panic when production kernels actually block in down_read under RCU."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:46:05.052Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/be9eaf2bb5db4ad3de61ef739fd268fd7f135737"},{"url":"https://git.kernel.org/stable/c/5b038319be442c620f774e6fc9e9283deeca1c75"}],"title":"bpf: Reject sleepable BPF_LSM_CGROUP programs at load time","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74338","datePublished":"2026-08-15T05:58:29.222Z","dateReserved":"2026-08-15T05:44:03.885Z","dateUpdated":"2026-08-17T05:46:05.052Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:22:34","lastModifiedDate":"2026-08-17 06:19:28","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:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74338","Ordinal":"1","Title":"bpf: Reject sleepable BPF_LSM_CGROUP programs at load time","CVE":"CVE-2026-74338","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74338","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject sleepable BPF_LSM_CGROUP programs at load time\n\nThe cgroup shim runs under rcu_read_lock_dont_migrate(), so we should\nnot attach any sleepable BPF programs there. Add support to the verifier\nto explicitly reject attempts to load sleepable BPF programs destined\nfor LSM cgroup attachment.\n\nWithout this, we get the following splat from a BPF_LSM_CGROUP\nprogram marked BPF_F_SLEEPABLE attached to file_open when it calls\nbpf_get_dentry_xattr():\n\n  BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1567\n  in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 34317, name: load\n  preempt_count: 0, expected: 0\n  RCU nest depth: 2, expected: 0\n  Call Trace:\n   down_read+0x76/0x480\n   ext4_xattr_get+0x11f/0x700\n   __vfs_getxattr+0xf0/0x150\n   bpf_get_dentry_xattr+0xbb/0xf0\n   bpf_prog_e76a298dac9218c6_test_open+0x6a/0x85\n   __cgroup_bpf_run_lsm_current+0x326/0x840\n   bpf_trampoline_6442534646+0x62/0x14d\n   security_file_open+0x34/0x60\n   do_dentry_open+0x340/0x1260\n   vfs_open+0x7a/0x440\n   path_openat+0x1bac/0x30a0\n\nlibbpf provides a .s named section variant for every sleepable\nprogram type except lsm_cgroup, reflecting that per-cgroup LSM programs\nare intended to only run in a non-sleepable context.\n\nThe above splat was obtained by bypassing libbpf by using bpf(2)\ndirectly.","Type":"Description","Title":"bpf: Reject sleepable BPF_LSM_CGROUP programs at load time"}]}}}