{"api_version":"1","generated_at":"2026-05-15T07:55:12+00:00","cve":"CVE-2026-43490","urls":{"html":"https://cve.report/CVE-2026-43490","api":"https://cve.report/api/cve/CVE-2026-43490.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43490","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43490"},"summary":{"title":"ksmbd: validate inherited ACE SID length","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate inherited ACE SID length\n\nsmb_inherit_dacl() walks the parent directory DACL loaded from the\nsecurity descriptor xattr. It verifies that each ACE contains the fixed\nSID header before using it, but does not verify that the variable-length\nSID described by sid.num_subauth is fully contained in the ACE.\n\nA malformed inheritable ACE can advertise more subauthorities than are\npresent in the ACE. compare_sids() may then read past the ACE.\nsmb_set_ace() also clamps the copied destination SID, but used the\nunchecked source SID count to compute the inherited ACE size. That could\nadvance the temporary inherited ACE buffer pointer and nt_size accounting\npast the allocated buffer.\n\nFix this by validating the parent ACE SID count and SID length before\nusing the SID during inheritance. Compute the inherited ACE size from the\ncopied SID so the size matches the bounded destination SID. Reject the\ninherited DACL if size accumulation would overflow smb_acl.size or the\nsecurity descriptor allocation size.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-15 06:16:20","updated_at":"2026-05-15 06:16:20"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/1aa60fea7f637c071f529ad6784aecca2f2f0c5f","name":"https://git.kernel.org/stable/c/1aa60fea7f637c071f529ad6784aecca2f2f0c5f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c1d95c995d5bcb24b639200a899eda59cb1e6d64","name":"https://git.kernel.org/stable/c/c1d95c995d5bcb24b639200a899eda59cb1e6d64","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/47c6e37a77b10e74f70d845ba4ea5d3cafa00336","name":"https://git.kernel.org/stable/c/47c6e37a77b10e74f70d845ba4ea5d3cafa00336","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/996454bc0da84d5a1dedb1a7861823087e01a7ae","name":"https://git.kernel.org/stable/c/996454bc0da84d5a1dedb1a7861823087e01a7ae","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43490","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43490","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 47c6e37a77b10e74f70d845ba4ea5d3cafa00336 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 1aa60fea7f637c071f529ad6784aecca2f2f0c5f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 c1d95c995d5bcb24b639200a899eda59cb1e6d64 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 996454bc0da84d5a1dedb1a7861823087e01a7ae git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.88 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.30 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.7 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1-rc3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/smb/server/smbacl.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"47c6e37a77b10e74f70d845ba4ea5d3cafa00336","status":"affected","version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","versionType":"git"},{"lessThan":"1aa60fea7f637c071f529ad6784aecca2f2f0c5f","status":"affected","version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","versionType":"git"},{"lessThan":"c1d95c995d5bcb24b639200a899eda59cb1e6d64","status":"affected","version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","versionType":"git"},{"lessThan":"996454bc0da84d5a1dedb1a7861823087e01a7ae","status":"affected","version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/smb/server/smbacl.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.15"},{"lessThan":"5.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.88","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.30","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.7","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1-rc3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.88","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.30","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.7","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1-rc3","versionStartIncluding":"5.15","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate inherited ACE SID length\n\nsmb_inherit_dacl() walks the parent directory DACL loaded from the\nsecurity descriptor xattr. It verifies that each ACE contains the fixed\nSID header before using it, but does not verify that the variable-length\nSID described by sid.num_subauth is fully contained in the ACE.\n\nA malformed inheritable ACE can advertise more subauthorities than are\npresent in the ACE. compare_sids() may then read past the ACE.\nsmb_set_ace() also clamps the copied destination SID, but used the\nunchecked source SID count to compute the inherited ACE size. That could\nadvance the temporary inherited ACE buffer pointer and nt_size accounting\npast the allocated buffer.\n\nFix this by validating the parent ACE SID count and SID length before\nusing the SID during inheritance. Compute the inherited ACE size from the\ncopied SID so the size matches the bounded destination SID. Reject the\ninherited DACL if size accumulation would overflow smb_acl.size or the\nsecurity descriptor allocation size."}],"providerMetadata":{"dateUpdated":"2026-05-15T05:15:37.666Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/47c6e37a77b10e74f70d845ba4ea5d3cafa00336"},{"url":"https://git.kernel.org/stable/c/1aa60fea7f637c071f529ad6784aecca2f2f0c5f"},{"url":"https://git.kernel.org/stable/c/c1d95c995d5bcb24b639200a899eda59cb1e6d64"},{"url":"https://git.kernel.org/stable/c/996454bc0da84d5a1dedb1a7861823087e01a7ae"}],"title":"ksmbd: validate inherited ACE SID length","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43490","datePublished":"2026-05-15T05:15:37.666Z","dateReserved":"2026-05-01T14:12:56.012Z","dateUpdated":"2026-05-15T05:15:37.666Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-15 06:16:20","lastModifiedDate":"2026-05-15 06:16:20","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43490","Ordinal":"1","Title":"ksmbd: validate inherited ACE SID length","CVE":"CVE-2026-43490","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43490","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate inherited ACE SID length\n\nsmb_inherit_dacl() walks the parent directory DACL loaded from the\nsecurity descriptor xattr. It verifies that each ACE contains the fixed\nSID header before using it, but does not verify that the variable-length\nSID described by sid.num_subauth is fully contained in the ACE.\n\nA malformed inheritable ACE can advertise more subauthorities than are\npresent in the ACE. compare_sids() may then read past the ACE.\nsmb_set_ace() also clamps the copied destination SID, but used the\nunchecked source SID count to compute the inherited ACE size. That could\nadvance the temporary inherited ACE buffer pointer and nt_size accounting\npast the allocated buffer.\n\nFix this by validating the parent ACE SID count and SID length before\nusing the SID during inheritance. Compute the inherited ACE size from the\ncopied SID so the size matches the bounded destination SID. Reject the\ninherited DACL if size accumulation would overflow smb_acl.size or the\nsecurity descriptor allocation size.","Type":"Description","Title":"ksmbd: validate inherited ACE SID length"}]}}}