{"api_version":"1","generated_at":"2026-09-26T17:30:13+00:00","cve":"CVE-2026-90251","urls":{"html":"https://cve.report/CVE-2026-90251","api":"https://cve.report/api/cve/CVE-2026-90251.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-90251","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-90251"},"summary":{"title":"Bluetooth: MSFT: validate evt_prefix_len against the response length","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: MSFT: validate evt_prefix_len against the response length\n\nread_supported_features() only checks that the response covers the fixed\npart of struct msft_rp_read_supported_features, which is 11 bytes:\n\n\tif (skb->len < sizeof(*rp)) {\n\t\tbt_dev_err(hdev, \"MSFT supported features length mismatch\");\n\t\tgoto failed;\n\t}\n\nevt_prefix[] is a flexible array member and rp->evt_prefix_len is an\nunvalidated u8 taken straight out of that response, so\n\n\tmsft->evt_prefix = kmemdup(rp->evt_prefix, rp->evt_prefix_len,\n\t\t\t\t   GFP_KERNEL);\n\ncopies up to 255 bytes from a reply that may have carried none of them.\nWhat is copied is data the controller never sent, and it is then used to\nmatch incoming vendor events in msft_vendor_evt().\n\nThis is not an out-of-bounds access. An skb data allocation always has\nat least SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) bytes past the\npayload, which is more than the 255 byte maximum, so the read stays\ninside the allocation and KASAN does not report it. It is still a read\nof bytes the host was never given, with the length fully controlled by\nthe controller.\n\nReject a response that is too short for the prefix it declares.\n\nVerified with an emulated controller over /dev/vhci on a KASAN kernel,\nwith vhci made to advertise an MSFT opcode the way btintel, btqca, btmtk\nand btrtl do unconditionally. A reply of exactly 11 bytes declaring\nevt_prefix_len = 255 reaches kmemdup and copies 255 bytes\n(\"skb->len=11 evt_prefix_len=255\", with the copied buffer dumped); since\nthe reply ends at the fixed part, all 255 come from past the end of the\nresponse. No KASAN report is produced, as expected from the allocation\nslack described above. With this patch the response is rejected with\n\"MSFT event prefix length mismatch\" and msft->evt_prefix is left unset.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-17 17:17:21","updated_at":"2026-09-17 17:17:21"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/7c2658023d839b651368a5b8b781bf9a817647cb","name":"https://git.kernel.org/stable/c/7c2658023d839b651368a5b8b781bf9a817647cb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/620c2631cff490d14d0b9d56f185cc745806d6d7","name":"https://git.kernel.org/stable/c/620c2631cff490d14d0b9d56f185cc745806d6d7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0079e1a944634ab2dc1c7cdec1144486d096407e","name":"https://git.kernel.org/stable/c/0079e1a944634ab2dc1c7cdec1144486d096407e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e804d54a5a99d99250490e68093eff7190472e6f","name":"https://git.kernel.org/stable/c/e804d54a5a99d99250490e68093eff7190472e6f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/63562cfaea8a650fdb31ee8de21c32e3600be642","name":"https://git.kernel.org/stable/c/63562cfaea8a650fdb31ee8de21c32e3600be642","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dce783a10e70f013410f5b583a29fc3286899629","name":"https://git.kernel.org/stable/c/dce783a10e70f013410f5b583a29fc3286899629","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/52b1b3b4d403cbda1b70ce2385e1a71f166a87ba","name":"https://git.kernel.org/stable/c/52b1b3b4d403cbda1b70ce2385e1a71f166a87ba","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/21f539c59ed330b671d75fd119c5f659ff92fbd1","name":"https://git.kernel.org/stable/c/21f539c59ed330b671d75fd119c5f659ff92fbd1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90251","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90251","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 dce783a10e70f013410f5b583a29fc3286899629 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 21f539c59ed330b671d75fd119c5f659ff92fbd1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 52b1b3b4d403cbda1b70ce2385e1a71f166a87ba git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 e804d54a5a99d99250490e68093eff7190472e6f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 620c2631cff490d14d0b9d56f185cc745806d6d7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 7c2658023d839b651368a5b8b781bf9a817647cb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 63562cfaea8a650fdb31ee8de21c32e3600be642 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 145373cb1b1fcdba2059e945d0aa2613af2e84d1 0079e1a944634ab2dc1c7cdec1144486d096407e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.8","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.8 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.270 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.221 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.188 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.157 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.110 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.52 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.6 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-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":["net/bluetooth/msft.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"dce783a10e70f013410f5b583a29fc3286899629","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"},{"lessThan":"21f539c59ed330b671d75fd119c5f659ff92fbd1","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"},{"lessThan":"52b1b3b4d403cbda1b70ce2385e1a71f166a87ba","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"},{"lessThan":"e804d54a5a99d99250490e68093eff7190472e6f","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"},{"lessThan":"620c2631cff490d14d0b9d56f185cc745806d6d7","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"},{"lessThan":"7c2658023d839b651368a5b8b781bf9a817647cb","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"},{"lessThan":"63562cfaea8a650fdb31ee8de21c32e3600be642","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"},{"lessThan":"0079e1a944634ab2dc1c7cdec1144486d096407e","status":"affected","version":"145373cb1b1fcdba2059e945d0aa2613af2e84d1","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/bluetooth/msft.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.8"},{"lessThan":"5.8","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.270","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.221","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.188","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.157","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.110","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.52","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.270","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.221","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.188","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.157","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.110","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.52","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.6","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"5.8","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: MSFT: validate evt_prefix_len against the response length\n\nread_supported_features() only checks that the response covers the fixed\npart of struct msft_rp_read_supported_features, which is 11 bytes:\n\n\tif (skb->len < sizeof(*rp)) {\n\t\tbt_dev_err(hdev, \"MSFT supported features length mismatch\");\n\t\tgoto failed;\n\t}\n\nevt_prefix[] is a flexible array member and rp->evt_prefix_len is an\nunvalidated u8 taken straight out of that response, so\n\n\tmsft->evt_prefix = kmemdup(rp->evt_prefix, rp->evt_prefix_len,\n\t\t\t\t   GFP_KERNEL);\n\ncopies up to 255 bytes from a reply that may have carried none of them.\nWhat is copied is data the controller never sent, and it is then used to\nmatch incoming vendor events in msft_vendor_evt().\n\nThis is not an out-of-bounds access. An skb data allocation always has\nat least SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) bytes past the\npayload, which is more than the 255 byte maximum, so the read stays\ninside the allocation and KASAN does not report it. It is still a read\nof bytes the host was never given, with the length fully controlled by\nthe controller.\n\nReject a response that is too short for the prefix it declares.\n\nVerified with an emulated controller over /dev/vhci on a KASAN kernel,\nwith vhci made to advertise an MSFT opcode the way btintel, btqca, btmtk\nand btrtl do unconditionally. A reply of exactly 11 bytes declaring\nevt_prefix_len = 255 reaches kmemdup and copies 255 bytes\n(\"skb->len=11 evt_prefix_len=255\", with the copied buffer dumped); since\nthe reply ends at the fixed part, all 255 come from past the end of the\nresponse. No KASAN report is produced, as expected from the allocation\nslack described above. With this patch the response is rejected with\n\"MSFT event prefix length mismatch\" and msft->evt_prefix is left unset."}],"providerMetadata":{"dateUpdated":"2026-09-17T16:07:52.066Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/dce783a10e70f013410f5b583a29fc3286899629"},{"url":"https://git.kernel.org/stable/c/21f539c59ed330b671d75fd119c5f659ff92fbd1"},{"url":"https://git.kernel.org/stable/c/52b1b3b4d403cbda1b70ce2385e1a71f166a87ba"},{"url":"https://git.kernel.org/stable/c/e804d54a5a99d99250490e68093eff7190472e6f"},{"url":"https://git.kernel.org/stable/c/620c2631cff490d14d0b9d56f185cc745806d6d7"},{"url":"https://git.kernel.org/stable/c/7c2658023d839b651368a5b8b781bf9a817647cb"},{"url":"https://git.kernel.org/stable/c/63562cfaea8a650fdb31ee8de21c32e3600be642"},{"url":"https://git.kernel.org/stable/c/0079e1a944634ab2dc1c7cdec1144486d096407e"}],"title":"Bluetooth: MSFT: validate evt_prefix_len against the response length","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-90251","datePublished":"2026-09-17T16:07:52.066Z","dateReserved":"2026-09-11T19:38:34.795Z","dateUpdated":"2026-09-17T16:07:52.066Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-17 17:17:21","lastModifiedDate":"2026-09-17 17:17:21","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"90251","Ordinal":"1","Title":"Bluetooth: MSFT: validate evt_prefix_len against the response le","CVE":"CVE-2026-90251","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"90251","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: MSFT: validate evt_prefix_len against the response length\n\nread_supported_features() only checks that the response covers the fixed\npart of struct msft_rp_read_supported_features, which is 11 bytes:\n\n\tif (skb->len < sizeof(*rp)) {\n\t\tbt_dev_err(hdev, \"MSFT supported features length mismatch\");\n\t\tgoto failed;\n\t}\n\nevt_prefix[] is a flexible array member and rp->evt_prefix_len is an\nunvalidated u8 taken straight out of that response, so\n\n\tmsft->evt_prefix = kmemdup(rp->evt_prefix, rp->evt_prefix_len,\n\t\t\t\t   GFP_KERNEL);\n\ncopies up to 255 bytes from a reply that may have carried none of them.\nWhat is copied is data the controller never sent, and it is then used to\nmatch incoming vendor events in msft_vendor_evt().\n\nThis is not an out-of-bounds access. An skb data allocation always has\nat least SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) bytes past the\npayload, which is more than the 255 byte maximum, so the read stays\ninside the allocation and KASAN does not report it. It is still a read\nof bytes the host was never given, with the length fully controlled by\nthe controller.\n\nReject a response that is too short for the prefix it declares.\n\nVerified with an emulated controller over /dev/vhci on a KASAN kernel,\nwith vhci made to advertise an MSFT opcode the way btintel, btqca, btmtk\nand btrtl do unconditionally. A reply of exactly 11 bytes declaring\nevt_prefix_len = 255 reaches kmemdup and copies 255 bytes\n(\"skb->len=11 evt_prefix_len=255\", with the copied buffer dumped); since\nthe reply ends at the fixed part, all 255 come from past the end of the\nresponse. No KASAN report is produced, as expected from the allocation\nslack described above. With this patch the response is rejected with\n\"MSFT event prefix length mismatch\" and msft->evt_prefix is left unset.","Type":"Description","Title":"Bluetooth: MSFT: validate evt_prefix_len against the response le"}]}}}