{"api_version":"1","generated_at":"2026-05-13T13:33:28+00:00","cve":"CVE-2026-31611","urls":{"html":"https://cve.report/CVE-2026-31611","api":"https://cve.report/api/cve/CVE-2026-31611.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-31611","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-31611"},"summary":{"title":"ksmbd: require 3 sub-authorities before reading sub_auth[2]","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: require 3 sub-authorities before reading sub_auth[2]\n\nparse_dacl() compares each ACE SID against sid_unix_NFS_mode and on\nmatch reads sid.sub_auth[2] as the file mode.  If sid_unix_NFS_mode is\nthe prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares\nonly min(num_subauth, 2) sub-authorities so a client SID with\nnum_subauth = 2 and sub_auth = {88, 3} will match.\n\nIf num_subauth = 2 and the ACE is placed at the very end of the security\ndescriptor, sub_auth[2] will be  4 bytes past end_of_acl.  The\nout-of-band bytes will then be masked to the low 9 bits and applied as\nthe file's POSIX mode, probably not something that is good to have\nhappen.\n\nFix this up by forcing the SID to actually carry a third sub-authority\nbefore reading it at all.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-04-24 15:16:40","updated_at":"2026-04-29 16:56:48"},"problem_types":["NVD-CWE-noinfo"],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.6","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","baseScore":8.6,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.6","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","data":{"baseScore":8.6,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/53370cf9090777774e07fd9a8ebce67c6cc333ab","name":"https://git.kernel.org/stable/c/53370cf9090777774e07fd9a8ebce67c6cc333ab","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d2454f4a002d08560a60f214f392e6491cf11560","name":"https://git.kernel.org/stable/c/d2454f4a002d08560a60f214f392e6491cf11560","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b5b5d5936a50497fb151c0b122899a6894721c2b","name":"https://git.kernel.org/stable/c/b5b5d5936a50497fb151c0b122899a6894721c2b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/46bbcd3ebfb3549c8da1838fc4493e79bd3241e7","name":"https://git.kernel.org/stable/c/46bbcd3ebfb3549c8da1838fc4493e79bd3241e7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a","name":"https://git.kernel.org/stable/c/9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/08f9e6d899b5c834bbcc239eae1bed58d9b15d2c","name":"https://git.kernel.org/stable/c/08f9e6d899b5c834bbcc239eae1bed58d9b15d2c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-31611","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31611","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 b5b5d5936a50497fb151c0b122899a6894721c2b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 08f9e6d899b5c834bbcc239eae1bed58d9b15d2c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 d2454f4a002d08560a60f214f392e6491cf11560 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 46bbcd3ebfb3549c8da1838fc4493e79bd3241e7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: require 3 sub-authorities before reading sub_auth[2]\n\nparse_dacl() compares each ACE SID against sid_unix_NFS_mode and on\nmatch reads sid.sub_auth[2] as the file mode.  If sid_unix_NFS_mode is\nthe prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares\nonly min(num_subauth, 2) sub-authorities so a client SID with\nnum_subauth = 2 and sub_auth = {88, 3} will match.\n\nIf num_subauth = 2 and the ACE is placed at the very end of the security\ndescriptor, sub_auth[2] will be  4 bytes past end_of_acl.  The\nout-of-band bytes will then be masked to the low 9 bits and applied as\nthe file's POSIX mode, probably not something that is good to have\nhappen.\n\nFix this up by forcing the SID to actually carry a third sub-authority\nbefore reading it at all."}],"metrics":[{"cvssV3_1":{"baseScore":8.6,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-04-27T14:04:23.206Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/b5b5d5936a50497fb151c0b122899a6894721c2b"},{"url":"https://git.kernel.org/stable/c/08f9e6d899b5c834bbcc239eae1bed58d9b15d2c"},{"url":"https://git.kernel.org/stable/c/d2454f4a002d08560a60f214f392e6491cf11560"},{"url":"https://git.kernel.org/stable/c/46bbcd3ebfb3549c8da1838fc4493e79bd3241e7"},{"url":"https://git.kernel.org/stable/c/9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a"},{"url":"https://git.kernel.org/stable/c/53370cf9090777774e07fd9a8ebce67c6cc333ab"}],"title":"ksmbd: require 3 sub-authorities before reading sub_auth[2]","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-31611","datePublished":"2026-04-24T14:42:32.124Z","dateReserved":"2026-03-09T15:48:24.122Z","dateUpdated":"2026-04-27T14:04:23.206Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-24 15:16:40","lastModifiedDate":"2026-04-29 16:56:48","problem_types":["NVD-CWE-noinfo"],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","baseScore":8.6,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":4.7}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.6.136","matchCriteriaId":"B1ABA9F0-A5C4-4CBE-92EC-33CA7D4F7634"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.83","matchCriteriaId":"7F0AE5B5-23AC-4DCC-B37A-51CA1DAE7BA8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.24","matchCriteriaId":"8126B8B8-6D0B-4443-86C1-672AEE893555"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19","versionEndExcluding":"6.19.14","matchCriteriaId":"D6A8A074-BBF4-4803-ABED-519A839435BB"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.0.1","matchCriteriaId":"9B5888AB-7403-4335-89E4-21CC0B48366A"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"31611","Ordinal":"1","Title":"ksmbd: require 3 sub-authorities before reading sub_auth[2]","CVE":"CVE-2026-31611","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"31611","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: require 3 sub-authorities before reading sub_auth[2]\n\nparse_dacl() compares each ACE SID against sid_unix_NFS_mode and on\nmatch reads sid.sub_auth[2] as the file mode.  If sid_unix_NFS_mode is\nthe prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares\nonly min(num_subauth, 2) sub-authorities so a client SID with\nnum_subauth = 2 and sub_auth = {88, 3} will match.\n\nIf num_subauth = 2 and the ACE is placed at the very end of the security\ndescriptor, sub_auth[2] will be  4 bytes past end_of_acl.  The\nout-of-band bytes will then be masked to the low 9 bits and applied as\nthe file's POSIX mode, probably not something that is good to have\nhappen.\n\nFix this up by forcing the SID to actually carry a third sub-authority\nbefore reading it at all.","Type":"Description","Title":"ksmbd: require 3 sub-authorities before reading sub_auth[2]"}]}}}