{ "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": "2026-10-16T19:05:59.372Z" }, "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" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74590", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:01:35.901397Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:05:59.372Z" } } ] } }