{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74590","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-15T05:44:03.918Z","datePublished":"2026-08-22T15:31:41.929Z","dateUpdated":"2026-08-25T05:40:17.568Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-25T05:40:17.568Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfsverity: Fix bpf_get_fsverity_digest() dynptr assumptions\n\nThe BPF verifier and the dynptr abstraction ensure that the memory space\nreferenced by a dynptr remains valid.  They do not, however, provide any\nguarantee that the contents of the memory are stable.  kfuncs are\nexpected to remain memory-safe even if concurrent modifications occur.\n\nbpf_get_fsverity_digest() didn't follow that: it could crash if\narg->digest_size was concurrently modified.\n\nFix that by using the known-good value hash_alg->digest_size instead.\n\nAlso widen 'dynptr_sz' and 'out_digest_sz' to u64 to match the return\ntype of __bpf_dynptr_size().  It doesn't appear that it can actually be\nmore than INT_MAX currently (since __bpf_dynptr_data_rw() excludes\nfile-based pointers), but the correct type might as well be used."}],"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 only reachable via bpf_get_fsverity_digest(), a BPF kfunc callable from BPF LSM programs loaded through the bpf(2) syscall and triggered by local LSM hooks such as file_open, not by any network-facing kernel service.\nAC:L - Exploitation requires racing concurrent writes to the dynptr-backed fsverity_digest buffer (e.g., bpf_map_update_elem from a sibling thread) against the kfunc's memset; the attacker controls both sides of this race and can repeat it until the bad offset is hit.\nPR:L - Loading and attaching the required BPF LSM program needs CAP_BPF and CAP_PERFMON, which an unprivileged user can obtain as root inside a user namespace (unshare -Ur) without init-namespace privileges, matching kernel CNA guidance for BPF reachability.\nUI:N - No victim interaction is required; the attacker can load the LSM program, prepare a shared dynptr buffer, enable fsverity on a file they own, and trigger file_open themselves to invoke the vulnerable kfunc.\nS:U - Successful exploitation corrupts kernel heap memory and can yield local privilege escalation within the same kernel/host security boundary; it does not by itself cross a guest-to-host, sandbox, or IOMMU isolation boundary.\nC:H - Concurrent tampering with digest_size lets memset() use an attacker-chosen offset beyond the dynptr allocation, causing out-of-bounds kernel heap writes that can corrupt adjacent objects and be leveraged for arbitrary kernel memory disclosure.\nI:H - The faulty memset() can write large zeroed regions far outside the dynptr buffer, giving a controllable out-of-bounds heap write primitive that is exploitable for control-flow hijacking and arbitrary kernel code execution.\nA:H - An out-of-bounds heap write from kernel context can immediately oops/panic the kernel or destabilize critical structures, and the underlying memory corruption reliably threatens system availability even before full exploitation."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/verity/measure.c"],"versions":[{"version":"67814c00de3161181cddd06c77aeaf86ac4cc584","lessThan":"1344b632cb5043e32939a84568125719111c5af3","status":"affected","versionType":"git"},{"version":"67814c00de3161181cddd06c77aeaf86ac4cc584","lessThan":"2a5cfcad1d56e26d645b7887b0ed24c371851525","status":"affected","versionType":"git"},{"version":"67814c00de3161181cddd06c77aeaf86ac4cc584","lessThan":"5bd63cad9df4328a184c409fbdad4f17944bcdb8","status":"affected","versionType":"git"},{"version":"67814c00de3161181cddd06c77aeaf86ac4cc584","lessThan":"3e8ec7c0387273329374f5c7bd61f5f38af71fe1","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/verity/measure.c"],"versions":[{"version":"6.8","status":"affected"},{"version":"0","lessThan":"6.8","status":"unaffected","versionType":"semver"},{"version":"6.12.104","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.45","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.9","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":"6.12.104"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.18.45"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.1.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/1344b632cb5043e32939a84568125719111c5af3"},{"url":"https://git.kernel.org/stable/c/2a5cfcad1d56e26d645b7887b0ed24c371851525"},{"url":"https://git.kernel.org/stable/c/5bd63cad9df4328a184c409fbdad4f17944bcdb8"},{"url":"https://git.kernel.org/stable/c/3e8ec7c0387273329374f5c7bd61f5f38af71fe1"}],"title":"fsverity: Fix bpf_get_fsverity_digest() dynptr assumptions","x_generator":{"engine":"bippy-1.2.0"}}}}