{"api_version":"1","generated_at":"2026-11-07T15:53:39+00:00","cve":"CVE-2026-99274","urls":{"html":"https://cve.report/CVE-2026-99274","api":"https://cve.report/api/cve/CVE-2026-99274.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-99274","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-99274"},"summary":{"title":"smb: client: fix fiemap wild read on empty truncated response","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix fiemap wild read on empty truncated response\n\nsmb3_fiemap() treats -E2BIG from SMB2_ioctl() as a truncated range blob\nand loops for the next chunk. If the server reports\nSTATUS_BUFFER_OVERFLOW with OutputCount == 0, SMB2_ioctl() returns\n-E2BIG with out_data == NULL and out_data_len == 0, and the existing\nlength checks accept the empty result. The loop then evaluates\n\n\tnext = out_data[num - 1].file_offset + ...\n\nwith num == 0, reading 16 bytes before NULL.\n\nReject a truncated range blob that contains no range, so the resume\noffset is never computed from an empty response. Also require the last\nrange in a truncated blob to advance the resume offset without\noverflowing, and to stay within the requested range; a malicious or\nbroken server could otherwise make no progress or underflow len and loop\nforever. Free the previous response buffer before retrying.\n\nReproduced on 6.6.87.2 with a malicious SMB2 server that answers\nFSCTL_QUERY_ALLOCATED_RANGES with STATUS_BUFFER_OVERFLOW and\nOutputCount == 0; an FS_IOC_FIEMAP ioctl on the mount oopses in\ncifs_fiemap() with CR2 = fffffffffffffff8. The code path is unchanged\non mainline.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-11-07 14:17:02","updated_at":"2026-11-07 14:17:02"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc","name":"https://git.kernel.org/stable/c/f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca","name":"https://git.kernel.org/stable/c/31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4a426ca5be7e3dedbe76575b967db04fbf01136f","name":"https://git.kernel.org/stable/c/4a426ca5be7e3dedbe76575b967db04fbf01136f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-99274","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99274","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4 4a426ca5be7e3dedbe76575b967db04fbf01136f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4 31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4 f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.2","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.61 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3.2 7.3.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.4-rc1 * 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/client/smb2ops.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"4a426ca5be7e3dedbe76575b967db04fbf01136f","status":"affected","version":"2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4","versionType":"git"},{"lessThan":"31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca","status":"affected","version":"2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4","versionType":"git"},{"lessThan":"f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc","status":"affected","version":"2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/smb/client/smb2ops.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.2"},{"lessThan":"5.2","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.61","versionType":"semver"},{"lessThanOrEqual":"7.3.*","status":"unaffected","version":"7.3.2","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.4-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.61","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3.2","versionStartIncluding":"5.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.4-rc1","versionStartIncluding":"5.2","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix fiemap wild read on empty truncated response\n\nsmb3_fiemap() treats -E2BIG from SMB2_ioctl() as a truncated range blob\nand loops for the next chunk. If the server reports\nSTATUS_BUFFER_OVERFLOW with OutputCount == 0, SMB2_ioctl() returns\n-E2BIG with out_data == NULL and out_data_len == 0, and the existing\nlength checks accept the empty result. The loop then evaluates\n\n\tnext = out_data[num - 1].file_offset + ...\n\nwith num == 0, reading 16 bytes before NULL.\n\nReject a truncated range blob that contains no range, so the resume\noffset is never computed from an empty response. Also require the last\nrange in a truncated blob to advance the resume offset without\noverflowing, and to stay within the requested range; a malicious or\nbroken server could otherwise make no progress or underflow len and loop\nforever. Free the previous response buffer before retrying.\n\nReproduced on 6.6.87.2 with a malicious SMB2 server that answers\nFSCTL_QUERY_ALLOCATED_RANGES with STATUS_BUFFER_OVERFLOW and\nOutputCount == 0; an FS_IOC_FIEMAP ioctl on the mount oopses in\ncifs_fiemap() with CR2 = fffffffffffffff8. The code path is unchanged\non mainline."}],"providerMetadata":{"dateUpdated":"2026-11-07T14:08:45.924Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/4a426ca5be7e3dedbe76575b967db04fbf01136f"},{"url":"https://git.kernel.org/stable/c/31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca"},{"url":"https://git.kernel.org/stable/c/f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc"}],"title":"smb: client: fix fiemap wild read on empty truncated response","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-99274","datePublished":"2026-11-07T14:08:45.924Z","dateReserved":"2026-09-25T10:25:14.405Z","dateUpdated":"2026-11-07T14:08:45.924Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-11-07 14:17:02","lastModifiedDate":"2026-11-07 14:17:02","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"99274","Ordinal":"1","Title":"smb: client: fix fiemap wild read on empty truncated response","CVE":"CVE-2026-99274","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"99274","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix fiemap wild read on empty truncated response\n\nsmb3_fiemap() treats -E2BIG from SMB2_ioctl() as a truncated range blob\nand loops for the next chunk. If the server reports\nSTATUS_BUFFER_OVERFLOW with OutputCount == 0, SMB2_ioctl() returns\n-E2BIG with out_data == NULL and out_data_len == 0, and the existing\nlength checks accept the empty result. The loop then evaluates\n\n\tnext = out_data[num - 1].file_offset + ...\n\nwith num == 0, reading 16 bytes before NULL.\n\nReject a truncated range blob that contains no range, so the resume\noffset is never computed from an empty response. Also require the last\nrange in a truncated blob to advance the resume offset without\noverflowing, and to stay within the requested range; a malicious or\nbroken server could otherwise make no progress or underflow len and loop\nforever. Free the previous response buffer before retrying.\n\nReproduced on 6.6.87.2 with a malicious SMB2 server that answers\nFSCTL_QUERY_ALLOCATED_RANGES with STATUS_BUFFER_OVERFLOW and\nOutputCount == 0; an FS_IOC_FIEMAP ioctl on the mount oopses in\ncifs_fiemap() with CR2 = fffffffffffffff8. The code path is unchanged\non mainline.","Type":"Description","Title":"smb: client: fix fiemap wild read on empty truncated response"}]}}}