{"api_version":"1","generated_at":"2026-09-15T10:57:40+00:00","cve":"CVE-2026-89632","urls":{"html":"https://cve.report/CVE-2026-89632","api":"https://cve.report/api/cve/CVE-2026-89632.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89632","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89632"},"summary":{"title":"smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()\n\nreparse_buf_ptr() reads buf->ReparseDataLength before checking that\ncount covers the full fixed header:\n\n    buf = (struct reparse_data_buffer *)((u8 *)io + off);\n    len = sizeof(*buf);                          /* 8 bytes */\n    rdlen = le16_to_cpu(buf->ReparseDataLength); /* offset 4, 2 bytes */\n\n    if (count < len || count < rdlen + len)      /* check comes after */\n\nstruct reparse_data_buffer has ReparseDataLength at offset 4.  If a\nserver returns OutputCount < 6, the read at offset 4-5 reaches past\nthe end of the received data.  The off+count bounds against iov_len\nwere already validated, but that does not protect against count being\nsmaller than sizeof(*buf).\n\nSplit the check: verify count >= sizeof(*buf) before reading\nReparseDataLength, then verify count covers the data region.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:48","updated_at":"2026-09-13 07:17:28"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","data":{"baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/05f78e6cf34ea3a285053bd5999e08e8ac298bd5","name":"https://git.kernel.org/stable/c/05f78e6cf34ea3a285053bd5999e08e8ac298bd5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/711cf71300d7992f450600df8864917d3538679f","name":"https://git.kernel.org/stable/c/711cf71300d7992f450600df8864917d3538679f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89632","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89632","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a158bb66b1373866d9fd5997565a58a573085539 711cf71300d7992f450600df8864917d3538679f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a158bb66b1373866d9fd5997565a58a573085539 05f78e6cf34ea3a285053bd5999e08e8ac298bd5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.32 7.2.4 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.32 7.3-rc1 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"89632","cve":"CVE-2026-89632","epss":"0.003180000","percentile":"0.246110000","score_date":"2026-09-14","updated_at":"2026-09-15 00:00:42"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/smb/client/smb2inode.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"711cf71300d7992f450600df8864917d3538679f","status":"affected","version":"a158bb66b1373866d9fd5997565a58a573085539","versionType":"git"},{"lessThan":"05f78e6cf34ea3a285053bd5999e08e8ac298bd5","status":"affected","version":"a158bb66b1373866d9fd5997565a58a573085539","versionType":"git"}]},{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/smb/client/smb2inode.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"7.2.4","status":"affected","version":"6.6.32","versionType":"semver"},{"lessThan":"7.3-rc1","status":"affected","version":"6.6.32","versionType":"semver"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"6.6.32","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"6.6.32","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()\n\nreparse_buf_ptr() reads buf->ReparseDataLength before checking that\ncount covers the full fixed header:\n\n    buf = (struct reparse_data_buffer *)((u8 *)io + off);\n    len = sizeof(*buf);                          /* 8 bytes */\n    rdlen = le16_to_cpu(buf->ReparseDataLength); /* offset 4, 2 bytes */\n\n    if (count < len || count < rdlen + len)      /* check comes after */\n\nstruct reparse_data_buffer has ReparseDataLength at offset 4.  If a\nserver returns OutputCount < 6, the read at offset 4-5 reaches past\nthe end of the received data.  The off+count bounds against iov_len\nwere already validated, but that does not protect against count being\nsmaller than sizeof(*buf).\n\nSplit the check: verify count >= sizeof(*buf) before reading\nReparseDataLength, then verify count covers the data region."}],"metrics":[{"cvssV3_1":{"baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - The flaw is in the in-kernel SMB client parser for FSCTL_GET_REPARSE_POINT IOCTL replies on TCP/445. A malicious, compromised, or on-path SMB server reaches reparse_buf_ptr() with crafted OutputOffset/OutputCount; this matches sibling client response-parsing scores such as CVE-2026-46155 and CVE-2024-49996.\nAC:L - The server fully controls OutputOffset and OutputCount. A successful IOCTL PDU with OutputCount < 6 and OutputOffset near iov_len (for example a 448-byte cifs_small_rq-sized frame) deterministically loads ReparseDataLength past the received payload, with no race or attacker-uncontrollable layout.\nPR:N - The attacker is the remote SMB server (or a MITM on an unsigned session) and needs no account, credentials, or capabilities on the victim client. GET_REPARSE runs on an already established tree connect after ordinary CREATE/lookup; the client authenticates to the server, not the reverse.\nUI:N - On an already-mounted or automounted CIFS share, any routine lookup/stat of a reparse point — including files the server flags as reparse in CREATE — issues FSCTL_GET_REPARSE_POINT. Backup jobs, indexers, and inode revalidation hit the parser with no contemporaneous victim mount action.\nS:U - The two-byte out-of-bounds load and any resulting oops stay inside the client kernel's security authority. The bug does not cross a VM, IOMMU, or sandbox boundary.\nC:L - The use-before-check reads exactly two bytes of ReparseDataLength past the IOCTL output region (and, when the PDU fills cifs_small_rq, past that 448-byte slab). Those bytes are passed only to smb_EIO2 tracing, so disclosure is strictly bounded, matching CVE-2026-64448 rather than unbounded heap leaks.\nI:N - The out-of-bounds access is a u16 load used only in the subsequent length check and error trace. On failure the helper returns -EIO and does not install a reparse tag or copy payload, so there is no kernel write or metadata-corruption primitive.\nA:H - A PDU that fills the cifs_small_rq or cifs_request slab with OutputOffset at the object end makes the two-byte load a true slab-out-of-bounds access, which KASAN reports as a BUG and which can oops/panic if the next page is unmapped. A malicious server can retrigger it on every GET_REPARSE."}]}],"providerMetadata":{"dateUpdated":"2026-09-13T06:32:11.058Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/711cf71300d7992f450600df8864917d3538679f"},{"url":"https://git.kernel.org/stable/c/05f78e6cf34ea3a285053bd5999e08e8ac298bd5"}],"title":"smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89632","datePublished":"2026-09-11T19:45:27.325Z","dateReserved":"2026-09-11T19:38:34.738Z","dateUpdated":"2026-09-13T06:32:11.058Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:48","lastModifiedDate":"2026-09-13 07:17:28","problem_types":[],"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:N/A:H","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":4.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89632","Ordinal":"1","Title":"smb: client: fix use-before-check of ReparseDataLength in repars","CVE":"CVE-2026-89632","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89632","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()\n\nreparse_buf_ptr() reads buf->ReparseDataLength before checking that\ncount covers the full fixed header:\n\n    buf = (struct reparse_data_buffer *)((u8 *)io + off);\n    len = sizeof(*buf);                          /* 8 bytes */\n    rdlen = le16_to_cpu(buf->ReparseDataLength); /* offset 4, 2 bytes */\n\n    if (count < len || count < rdlen + len)      /* check comes after */\n\nstruct reparse_data_buffer has ReparseDataLength at offset 4.  If a\nserver returns OutputCount < 6, the read at offset 4-5 reaches past\nthe end of the received data.  The off+count bounds against iov_len\nwere already validated, but that does not protect against count being\nsmaller than sizeof(*buf).\n\nSplit the check: verify count >= sizeof(*buf) before reading\nReparseDataLength, then verify count covers the data region.","Type":"Description","Title":"smb: client: fix use-before-check of ReparseDataLength in repars"}]}}}