{"api_version":"1","generated_at":"2026-07-20T23:54:04+00:00","cve":"CVE-2026-63996","urls":{"html":"https://cve.report/CVE-2026-63996","api":"https://cve.report/api/cve/CVE-2026-63996.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63996","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63996"},"summary":{"title":"ethtool: cmis: require exact CDB reply length","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nethtool: cmis: require exact CDB reply length\n\nMalicious SFP module could respond with rpl_len longer than\nwhat cmis_cdb_process_reply() expected, leading to OOB writes.\nMalicious HW is a bit theoretical but some modules may just\nbe buggy and/or the reads may occasionally get corrupted,\nso let's protect the kernel.\n\nThe existing check protects from short replies. We need to\nprotect from long ones, too. All callers that pass a non-zero\nrpl_exp_len cast the reply payload to a fixed-layout struct\nand read fields at fixed offsets, with no version negotiation\nor short-reply handling:\n\n  - cmis_cdb_validate_password()\n  - cmis_cdb_module_features_get()\n  - cmis_fw_update_fw_mng_features_get()\n\nso let's assume that responses longer than expected do not\nhave to be handled gracefully here. Add a warning message\nto make the debug easier in case my understanding is wrong...\n\nNote that page_data->length (argument of kmalloc) comes from\nlast arg to ethtool_cmis_page_init() which is rpl_exp_len.\n\nNote2 that AIs also like to point out overflows in args->req.payload\nitself (which is a fixed-size 120 B buffer, on the stack),\nbut callers should be reading structs defined by the standard,\nso protecting from requests for more data than max seem like\ndefensive programming.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:39","updated_at":"2026-07-20 15:17:01"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1","name":"https://git.kernel.org/stable/c/4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3","name":"https://git.kernel.org/stable/c/2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3","name":"https://git.kernel.org/stable/c/eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1","name":"https://git.kernel.org/stable/c/6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63996","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63996","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a39c84d796254e6b1662ca0c46dbc313379e9291 2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a39c84d796254e6b1662ca0c46dbc313379e9291 4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a39c84d796254e6b1662ca0c46dbc313379e9291 eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a39c84d796254e6b1662ca0c46dbc313379e9291 6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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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":["net/ethtool/cmis_cdb.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3","status":"affected","version":"a39c84d796254e6b1662ca0c46dbc313379e9291","versionType":"git"},{"lessThan":"4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1","status":"affected","version":"a39c84d796254e6b1662ca0c46dbc313379e9291","versionType":"git"},{"lessThan":"eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3","status":"affected","version":"a39c84d796254e6b1662ca0c46dbc313379e9291","versionType":"git"},{"lessThan":"6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1","status":"affected","version":"a39c84d796254e6b1662ca0c46dbc313379e9291","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ethtool/cmis_cdb.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.11"},{"lessThan":"6.11","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.93","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.35","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.12","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":"6.12.93","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.35","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.12","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nethtool: cmis: require exact CDB reply length\n\nMalicious SFP module could respond with rpl_len longer than\nwhat cmis_cdb_process_reply() expected, leading to OOB writes.\nMalicious HW is a bit theoretical but some modules may just\nbe buggy and/or the reads may occasionally get corrupted,\nso let's protect the kernel.\n\nThe existing check protects from short replies. We need to\nprotect from long ones, too. All callers that pass a non-zero\nrpl_exp_len cast the reply payload to a fixed-layout struct\nand read fields at fixed offsets, with no version negotiation\nor short-reply handling:\n\n  - cmis_cdb_validate_password()\n  - cmis_cdb_module_features_get()\n  - cmis_fw_update_fw_mng_features_get()\n\nso let's assume that responses longer than expected do not\nhave to be handled gracefully here. Add a warning message\nto make the debug easier in case my understanding is wrong...\n\nNote that page_data->length (argument of kmalloc) comes from\nlast arg to ethtool_cmis_page_init() which is rpl_exp_len.\n\nNote2 that AIs also like to point out overflows in args->req.payload\nitself (which is a fixed-size 120 B buffer, on the stack),\nbut callers should be reading structs defined by the standard,\nso protecting from requests for more data than max seem like\ndefensive programming."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-20T13:42:11.911Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3"},{"url":"https://git.kernel.org/stable/c/4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1"},{"url":"https://git.kernel.org/stable/c/eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3"},{"url":"https://git.kernel.org/stable/c/6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1"}],"title":"ethtool: cmis: require exact CDB reply length","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63996","datePublished":"2026-07-19T14:56:15.256Z","dateReserved":"2026-07-19T07:54:57.026Z","dateUpdated":"2026-07-20T13:42:11.911Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:39","lastModifiedDate":"2026-07-20 15:17:01","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63996","Ordinal":"1","Title":"ethtool: cmis: require exact CDB reply length","CVE":"CVE-2026-63996","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63996","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nethtool: cmis: require exact CDB reply length\n\nMalicious SFP module could respond with rpl_len longer than\nwhat cmis_cdb_process_reply() expected, leading to OOB writes.\nMalicious HW is a bit theoretical but some modules may just\nbe buggy and/or the reads may occasionally get corrupted,\nso let's protect the kernel.\n\nThe existing check protects from short replies. We need to\nprotect from long ones, too. All callers that pass a non-zero\nrpl_exp_len cast the reply payload to a fixed-layout struct\nand read fields at fixed offsets, with no version negotiation\nor short-reply handling:\n\n  - cmis_cdb_validate_password()\n  - cmis_cdb_module_features_get()\n  - cmis_fw_update_fw_mng_features_get()\n\nso let's assume that responses longer than expected do not\nhave to be handled gracefully here. Add a warning message\nto make the debug easier in case my understanding is wrong...\n\nNote that page_data->length (argument of kmalloc) comes from\nlast arg to ethtool_cmis_page_init() which is rpl_exp_len.\n\nNote2 that AIs also like to point out overflows in args->req.payload\nitself (which is a fixed-size 120 B buffer, on the stack),\nbut callers should be reading structs defined by the standard,\nso protecting from requests for more data than max seem like\ndefensive programming.","Type":"Description","Title":"ethtool: cmis: require exact CDB reply length"}]}}}