{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31717", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.134Z", "datePublished": "2026-05-01T13:56:12.012Z", "dateUpdated": "2026-08-05T12:24:48.598Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:24:48.598Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate owner of durable handle on reconnect\n\nCurrently, ksmbd does not verify if the user attempting to reconnect\nto a durable handle is the same user who originally opened the file.\nThis allows any authenticated user to hijack an orphaned durable handle\nby predicting or brute-forcing the persistent ID.\n\nAccording to MS-SMB2, the server MUST verify that the SecurityContext\nof the reconnect request matches the SecurityContext associated with\nthe existing open.\nAdd a durable_owner structure to ksmbd_file to store the original opener's\nUID, GID, and account name. and catpure the owner information when a file\nhandle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner()\nto validate the identity of the requester during SMB2_CREATE (DHnC)." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - ksmbd is an in-kernel SMB server reachable over the network via SMB requests, including SMB2 CREATE durable-handle reconnects.\nAC:L - Exploitation does not require a race or conditions outside attacker control; an attacker can send reconnect requests and predict or brute-force the global persistent ID in a reasonable multi-user durable-handle deployment.\nPR:L - The SMB2 CREATE path requires a valid authenticated session and tree connection before reaching the vulnerable durable reconnect logic. The flaw allows any authenticated SMB user to hijack another user's orphaned durable handle.\nUI:N - No victim interaction is required at exploit time; the attacker sends network SMB requests directly to the server.\nS:U - The impact remains within the ksmbd/file-server security authority and does not cross a VM, sandbox, or hardware isolation boundary.\nC:H - A hijacked durable handle can be used to read victim-opened files using the original handle's access rights, bypassing normal open-time ACL checks. This can expose full contents of sensitive files.\nI:H - The reconnected handle reuses the original `fp->daccess`, so if the victim handle had write, set-info, rename, truncate, or delete rights, the attacker can modify victim data with those rights.\nA:H - The attacker can steal or close the durable handle and, when the original handle carries write/delete/truncate rights, render victim data or critical shared files unavailable." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/mgmt/user_session.c", "fs/smb/server/oplock.c", "fs/smb/server/oplock.h", "fs/smb/server/smb2pdu.c", "fs/smb/server/vfs_cache.c", "fs/smb/server/vfs_cache.h" ], "versions": [ { "version": "8df4bcdb0a4232192b2445256c39b787d58ef14d", "lessThan": "712cdf917e77a6444ce3836874829d770db20ee6", "status": "affected", "versionType": "git" }, { "version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d", "status": "affected", "versionType": "git" }, { "version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "00ce8d6789dae72d042a4522264964c72891ca37", "status": "affected", "versionType": "git" }, { "version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "c908c853f304a4969b5aa10eba0b50350cc65b80", "status": "affected", "versionType": "git" }, { "version": "c8efcc786146a951091588e5fa7e3c754850cb3c", "lessThan": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a", "status": "affected", "versionType": "git" }, { "version": "6.6.32", "lessThan": "6.6.142", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/smb/server/mgmt/user_session.c", "fs/smb/server/oplock.c", "fs/smb/server/oplock.h", "fs/smb/server/smb2pdu.c", "fs/smb/server/vfs_cache.c", "fs/smb/server/vfs_cache.h" ], "versions": [ { "version": "6.9", "status": "affected" }, { "version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.142", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.25", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.2", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "6.6.32", "versionEndExcluding": "6.6.142" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.12.92" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.25" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.0.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/712cdf917e77a6444ce3836874829d770db20ee6" }, { "url": "https://git.kernel.org/stable/c/c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d" }, { "url": "https://git.kernel.org/stable/c/00ce8d6789dae72d042a4522264964c72891ca37" }, { "url": "https://git.kernel.org/stable/c/c908c853f304a4969b5aa10eba0b50350cc65b80" }, { "url": "https://git.kernel.org/stable/c/49110a8ce654bbe56bef7c5e44cce31f4b102b8a" } ], "title": "ksmbd: validate owner of durable handle on reconnect", "x_generator": { "engine": "bippy-1.2.0" } } } }