{"api_version":"1","generated_at":"2026-09-11T00:34:43+00:00","cve":"CVE-2026-80876","urls":{"html":"https://cve.report/CVE-2026-80876","api":"https://cve.report/api/cve/CVE-2026-80876.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80876","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80876"},"summary":{"title":"ring-buffer: Fix event length with forced 8-byte alignment","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix event length with forced 8-byte alignment\n\nWhen RB_FORCE_8BYTE_ALIGNMENT is true, rb_calculate_event_length()\nreserves the space of event->array[0] for placing the data length and\nrb_update_event() stores the data length in event->array[0]\naccordingly. As a result the whole event length will add extra 4 bytes\nfor sizeof(event.array[0]) unconditionally.\n\nBut ring_buffer_event_length() only subtracts the\nsizeof(event->array[0]) for events larger than RB_MAX_SMALL_DATA +\nsizeof(event->array[0]). As a result, small events on architectures\nwith RB_FORCE_8BYTE_ALIGNMENT=true report a data length that is 4\nbytes larger than expected.\n\nTo fix it, add the RB_FORCE_8BYTE_ALIGNMENT as a condition to subtract\nthe size of that length field whenever RB_FORCE_8BYTE_ALIGNMENT is\ntrue.\n\nThis issue is observed in a riscv64 kernel with\nCONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, when we run ftrace selftest\ntrace_marker_raw.tc, we get the weird log: for cases where the id is\n1..100, the number of data field is 8*N, but once id exceeds 100, the\nnumber of data field becomes 8*N+4:\n # 1 buf: 58 00 00 00 80 5e d1 63 (number of data field is 8*1)\n ...\n # a buf: 58 ...                  (number of data field is 8*2)\n ...\n # 64 buf: 58 ...                 (number of data field is 8*13)\n # 65 buf: 58 ...                 (number of data field is 8*13+4)\n\nAfter applying this change, the number of data field keeps being 8*N+4\nconsistently.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-04 17:16:59","updated_at":"2026-09-04 17:16:59"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/7c9f0ccf9f04142458d2ac3d39414f4acae242f0","name":"https://git.kernel.org/stable/c/7c9f0ccf9f04142458d2ac3d39414f4acae242f0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cfada73fabe2ccc06ec77fe2ceaa088689213326","name":"https://git.kernel.org/stable/c/cfada73fabe2ccc06ec77fe2ceaa088689213326","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992","name":"https://git.kernel.org/stable/c/3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ec5e96aee75d27779b9a860307679f13f33adb0c","name":"https://git.kernel.org/stable/c/ec5e96aee75d27779b9a860307679f13f33adb0c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/14057268e79654c3e8ea2c9b5204cb9644b2964d","name":"https://git.kernel.org/stable/c/14057268e79654c3e8ea2c9b5204cb9644b2964d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dbcb8635b1eb7603818591cf745c7b1d714f7ac6","name":"https://git.kernel.org/stable/c/dbcb8635b1eb7603818591cf745c7b1d714f7ac6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0","name":"https://git.kernel.org/stable/c/c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/24c3fa71f9947b0e1f3b954db1b769b44140192e","name":"https://git.kernel.org/stable/c/24c3fa71f9947b0e1f3b954db1b769b44140192e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80876","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80876","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 7c9f0ccf9f04142458d2ac3d39414f4acae242f0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 24c3fa71f9947b0e1f3b954db1b769b44140192e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 14057268e79654c3e8ea2c9b5204cb9644b2964d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 dbcb8635b1eb7603818591cf745c7b1d714f7ac6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80876","cve":"CVE-2026-80876","epss":"0.001640000","percentile":"0.059220000","score_date":"2026-09-07","updated_at":"2026-09-08 00:05:26"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/trace/ring_buffer.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"7c9f0ccf9f04142458d2ac3d39414f4acae242f0","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"},{"lessThan":"24c3fa71f9947b0e1f3b954db1b769b44140192e","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"},{"lessThan":"14057268e79654c3e8ea2c9b5204cb9644b2964d","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"},{"lessThan":"dbcb8635b1eb7603818591cf745c7b1d714f7ac6","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"},{"lessThan":"cfada73fabe2ccc06ec77fe2ceaa088689213326","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"},{"lessThan":"ec5e96aee75d27779b9a860307679f13f33adb0c","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"},{"lessThan":"3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"},{"lessThan":"c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0","status":"affected","version":"2271048d1b3b0aabf83d25b29c20646dcabedc05","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/trace/ring_buffer.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.34"},{"lessThan":"2.6.34","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.261","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.212","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.261","versionStartIncluding":"2.6.34","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.212","versionStartIncluding":"2.6.34","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"2.6.34","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"2.6.34","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"2.6.34","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"2.6.34","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"2.6.34","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"2.6.34","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix event length with forced 8-byte alignment\n\nWhen RB_FORCE_8BYTE_ALIGNMENT is true, rb_calculate_event_length()\nreserves the space of event->array[0] for placing the data length and\nrb_update_event() stores the data length in event->array[0]\naccordingly. As a result the whole event length will add extra 4 bytes\nfor sizeof(event.array[0]) unconditionally.\n\nBut ring_buffer_event_length() only subtracts the\nsizeof(event->array[0]) for events larger than RB_MAX_SMALL_DATA +\nsizeof(event->array[0]). As a result, small events on architectures\nwith RB_FORCE_8BYTE_ALIGNMENT=true report a data length that is 4\nbytes larger than expected.\n\nTo fix it, add the RB_FORCE_8BYTE_ALIGNMENT as a condition to subtract\nthe size of that length field whenever RB_FORCE_8BYTE_ALIGNMENT is\ntrue.\n\nThis issue is observed in a riscv64 kernel with\nCONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, when we run ftrace selftest\ntrace_marker_raw.tc, we get the weird log: for cases where the id is\n1..100, the number of data field is 8*N, but once id exceeds 100, the\nnumber of data field becomes 8*N+4:\n # 1 buf: 58 00 00 00 80 5e d1 63 (number of data field is 8*1)\n ...\n # a buf: 58 ...                  (number of data field is 8*2)\n ...\n # 64 buf: 58 ...                 (number of data field is 8*13)\n # 65 buf: 58 ...                 (number of data field is 8*13+4)\n\nAfter applying this change, the number of data field keeps being 8*N+4\nconsistently."}],"providerMetadata":{"dateUpdated":"2026-09-04T16:48:50.082Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/7c9f0ccf9f04142458d2ac3d39414f4acae242f0"},{"url":"https://git.kernel.org/stable/c/24c3fa71f9947b0e1f3b954db1b769b44140192e"},{"url":"https://git.kernel.org/stable/c/14057268e79654c3e8ea2c9b5204cb9644b2964d"},{"url":"https://git.kernel.org/stable/c/dbcb8635b1eb7603818591cf745c7b1d714f7ac6"},{"url":"https://git.kernel.org/stable/c/cfada73fabe2ccc06ec77fe2ceaa088689213326"},{"url":"https://git.kernel.org/stable/c/ec5e96aee75d27779b9a860307679f13f33adb0c"},{"url":"https://git.kernel.org/stable/c/3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992"},{"url":"https://git.kernel.org/stable/c/c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0"}],"title":"ring-buffer: Fix event length with forced 8-byte alignment","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80876","datePublished":"2026-09-04T16:48:50.082Z","dateReserved":"2026-08-26T14:34:25.799Z","dateUpdated":"2026-09-04T16:48:50.082Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-04 17:16:59","lastModifiedDate":"2026-09-04 17:16:59","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80876","Ordinal":"1","Title":"ring-buffer: Fix event length with forced 8-byte alignment","CVE":"CVE-2026-80876","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80876","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix event length with forced 8-byte alignment\n\nWhen RB_FORCE_8BYTE_ALIGNMENT is true, rb_calculate_event_length()\nreserves the space of event->array[0] for placing the data length and\nrb_update_event() stores the data length in event->array[0]\naccordingly. As a result the whole event length will add extra 4 bytes\nfor sizeof(event.array[0]) unconditionally.\n\nBut ring_buffer_event_length() only subtracts the\nsizeof(event->array[0]) for events larger than RB_MAX_SMALL_DATA +\nsizeof(event->array[0]). As a result, small events on architectures\nwith RB_FORCE_8BYTE_ALIGNMENT=true report a data length that is 4\nbytes larger than expected.\n\nTo fix it, add the RB_FORCE_8BYTE_ALIGNMENT as a condition to subtract\nthe size of that length field whenever RB_FORCE_8BYTE_ALIGNMENT is\ntrue.\n\nThis issue is observed in a riscv64 kernel with\nCONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, when we run ftrace selftest\ntrace_marker_raw.tc, we get the weird log: for cases where the id is\n1..100, the number of data field is 8*N, but once id exceeds 100, the\nnumber of data field becomes 8*N+4:\n # 1 buf: 58 00 00 00 80 5e d1 63 (number of data field is 8*1)\n ...\n # a buf: 58 ...                  (number of data field is 8*2)\n ...\n # 64 buf: 58 ...                 (number of data field is 8*13)\n # 65 buf: 58 ...                 (number of data field is 8*13+4)\n\nAfter applying this change, the number of data field keeps being 8*N+4\nconsistently.","Type":"Description","Title":"ring-buffer: Fix event length with forced 8-byte alignment"}]}}}