{"api_version":"1","generated_at":"2026-06-24T23:23:27+00:00","cve":"CVE-2026-52996","urls":{"html":"https://cve.report/CVE-2026-52996","api":"https://cve.report/api/cve/CVE-2026-52996.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-52996","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-52996"},"summary":{"title":"ksmbd: fix durable fd leak on ClientGUID mismatch in durable v2 open","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix durable fd leak on ClientGUID mismatch in durable v2 open\n\nksmbd_lookup_fd_cguid() returns a ksmbd_file with its refcount\nincremented via ksmbd_fp_get(). parse_durable_handle_context() in\nthe DURABLE_REQ_V2 case properly releases this reference on every\npath inside the ClientGUID-match branch, either by calling\nksmbd_put_durable_fd() or by transferring ownership to dh_info->fp\nfor a successful reconnect. However, when an entry exists in the\nglobal file table with the same CreateGuid but a different\nClientGUID, the code simply falls through to the new-open path\nwithout dropping the reference obtained from ksmbd_lookup_fd_cguid().\n\nPer MS-SMB2 section 3.3.5.9.10 (\"Handling the\nSMB2_CREATE_DURABLE_HANDLE_REQUEST_V2 Create Context\"), the server\nMUST locate an Open whose Open.CreateGuid matches the request's\nCreateGuid AND whose Open.ClientGuid matches the ClientGuid of the\nconnection that received the request. If no such Open is found, the\nserver MUST continue with the normal open execution phase. A\nCreateGuid hit with a ClientGUID mismatch is therefore the\n\"Open not found\" case: proceeding with a new open is correct, but\nthe reference obtained purely as a side effect of the lookup must\nnot be leaked.\n\nRepeated requests that hit this mismatch pin global_ft entries,\nprevent __ksmbd_close_fd() from ever running for the corresponding\nfiles, and defeat the durable scavenger, leading to long-lived\nresource leaks.\n\nRelease the reference in the mismatch path and clear dh_info->fp so\nsubsequent logic does not mistake a non-matching lookup result for\na reconnect target.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-06-24 17:17:10","updated_at":"2026-06-24 17:17:10"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/06f709d0e531f3e54d88665dd426be3998a774e6","name":"https://git.kernel.org/stable/c/06f709d0e531f3e54d88665dd426be3998a774e6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f31beef633fbf2b5af7805fa187a10bcff1d4b49","name":"https://git.kernel.org/stable/c/f31beef633fbf2b5af7805fa187a10bcff1d4b49","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/407b6e699ba8b45b72cc265eed8a1bc8a7191609","name":"https://git.kernel.org/stable/c/407b6e699ba8b45b72cc265eed8a1bc8a7191609","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8c4a0ef19c8264c150833131af34541495832cd0","name":"https://git.kernel.org/stable/c/8c4a0ef19c8264c150833131af34541495832cd0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/804054d19886ac6628883d82410f6ee42a818664","name":"https://git.kernel.org/stable/c/804054d19886ac6628883d82410f6ee42a818664","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-52996","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52996","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8df4bcdb0a4232192b2445256c39b787d58ef14d 407b6e699ba8b45b72cc265eed8a1bc8a7191609 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c8efcc786146a951091588e5fa7e3c754850cb3c f31beef633fbf2b5af7805fa187a10bcff1d4b49 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c8efcc786146a951091588e5fa7e3c754850cb3c 06f709d0e531f3e54d88665dd426be3998a774e6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c8efcc786146a951091588e5fa7e3c754850cb3c 8c4a0ef19c8264c150833131af34541495832cd0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c8efcc786146a951091588e5fa7e3c754850cb3c 804054d19886ac6628883d82410f6ee42a818664 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.32 6.6.141 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.9","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.9 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.141 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.91 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.33 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.10 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * 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/smb2pdu.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"407b6e699ba8b45b72cc265eed8a1bc8a7191609","status":"affected","version":"8df4bcdb0a4232192b2445256c39b787d58ef14d","versionType":"git"},{"lessThan":"f31beef633fbf2b5af7805fa187a10bcff1d4b49","status":"affected","version":"c8efcc786146a951091588e5fa7e3c754850cb3c","versionType":"git"},{"lessThan":"06f709d0e531f3e54d88665dd426be3998a774e6","status":"affected","version":"c8efcc786146a951091588e5fa7e3c754850cb3c","versionType":"git"},{"lessThan":"8c4a0ef19c8264c150833131af34541495832cd0","status":"affected","version":"c8efcc786146a951091588e5fa7e3c754850cb3c","versionType":"git"},{"lessThan":"804054d19886ac6628883d82410f6ee42a818664","status":"affected","version":"c8efcc786146a951091588e5fa7e3c754850cb3c","versionType":"git"},{"lessThan":"6.6.141","status":"affected","version":"6.6.32","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/smb/server/smb2pdu.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.9"},{"lessThan":"6.9","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.141","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.91","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.33","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.141","versionStartIncluding":"6.6.32","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.91","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.33","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.10","versionStartIncluding":"6.9","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.9","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix durable fd leak on ClientGUID mismatch in durable v2 open\n\nksmbd_lookup_fd_cguid() returns a ksmbd_file with its refcount\nincremented via ksmbd_fp_get(). parse_durable_handle_context() in\nthe DURABLE_REQ_V2 case properly releases this reference on every\npath inside the ClientGUID-match branch, either by calling\nksmbd_put_durable_fd() or by transferring ownership to dh_info->fp\nfor a successful reconnect. However, when an entry exists in the\nglobal file table with the same CreateGuid but a different\nClientGUID, the code simply falls through to the new-open path\nwithout dropping the reference obtained from ksmbd_lookup_fd_cguid().\n\nPer MS-SMB2 section 3.3.5.9.10 (\"Handling the\nSMB2_CREATE_DURABLE_HANDLE_REQUEST_V2 Create Context\"), the server\nMUST locate an Open whose Open.CreateGuid matches the request's\nCreateGuid AND whose Open.ClientGuid matches the ClientGuid of the\nconnection that received the request. If no such Open is found, the\nserver MUST continue with the normal open execution phase. A\nCreateGuid hit with a ClientGUID mismatch is therefore the\n\"Open not found\" case: proceeding with a new open is correct, but\nthe reference obtained purely as a side effect of the lookup must\nnot be leaked.\n\nRepeated requests that hit this mismatch pin global_ft entries,\nprevent __ksmbd_close_fd() from ever running for the corresponding\nfiles, and defeat the durable scavenger, leading to long-lived\nresource leaks.\n\nRelease the reference in the mismatch path and clear dh_info->fp so\nsubsequent logic does not mistake a non-matching lookup result for\na reconnect target."}],"providerMetadata":{"dateUpdated":"2026-06-24T16:29:09.113Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/407b6e699ba8b45b72cc265eed8a1bc8a7191609"},{"url":"https://git.kernel.org/stable/c/f31beef633fbf2b5af7805fa187a10bcff1d4b49"},{"url":"https://git.kernel.org/stable/c/06f709d0e531f3e54d88665dd426be3998a774e6"},{"url":"https://git.kernel.org/stable/c/8c4a0ef19c8264c150833131af34541495832cd0"},{"url":"https://git.kernel.org/stable/c/804054d19886ac6628883d82410f6ee42a818664"}],"title":"ksmbd: fix durable fd leak on ClientGUID mismatch in durable v2 open","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-52996","datePublished":"2026-06-24T16:29:09.113Z","dateReserved":"2026-06-09T07:44:35.377Z","dateUpdated":"2026-06-24T16:29:09.113Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-24 17:17:10","lastModifiedDate":"2026-06-24 17:17:10","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"52996","Ordinal":"1","Title":"ksmbd: fix durable fd leak on ClientGUID mismatch in durable v2 ","CVE":"CVE-2026-52996","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"52996","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix durable fd leak on ClientGUID mismatch in durable v2 open\n\nksmbd_lookup_fd_cguid() returns a ksmbd_file with its refcount\nincremented via ksmbd_fp_get(). parse_durable_handle_context() in\nthe DURABLE_REQ_V2 case properly releases this reference on every\npath inside the ClientGUID-match branch, either by calling\nksmbd_put_durable_fd() or by transferring ownership to dh_info->fp\nfor a successful reconnect. However, when an entry exists in the\nglobal file table with the same CreateGuid but a different\nClientGUID, the code simply falls through to the new-open path\nwithout dropping the reference obtained from ksmbd_lookup_fd_cguid().\n\nPer MS-SMB2 section 3.3.5.9.10 (\"Handling the\nSMB2_CREATE_DURABLE_HANDLE_REQUEST_V2 Create Context\"), the server\nMUST locate an Open whose Open.CreateGuid matches the request's\nCreateGuid AND whose Open.ClientGuid matches the ClientGuid of the\nconnection that received the request. If no such Open is found, the\nserver MUST continue with the normal open execution phase. A\nCreateGuid hit with a ClientGUID mismatch is therefore the\n\"Open not found\" case: proceeding with a new open is correct, but\nthe reference obtained purely as a side effect of the lookup must\nnot be leaked.\n\nRepeated requests that hit this mismatch pin global_ft entries,\nprevent __ksmbd_close_fd() from ever running for the corresponding\nfiles, and defeat the durable scavenger, leading to long-lived\nresource leaks.\n\nRelease the reference in the mismatch path and clear dh_info->fp so\nsubsequent logic does not mistake a non-matching lookup result for\na reconnect target.","Type":"Description","Title":"ksmbd: fix durable fd leak on ClientGUID mismatch in durable v2 "}]}}}