{"api_version":"1","generated_at":"2026-08-13T15:30:12+00:00","cve":"CVE-2026-68370","urls":{"html":"https://cve.report/CVE-2026-68370","api":"https://cve.report/api/cve/CVE-2026-68370.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-68370","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-68370"},"summary":{"title":"usb: gadget: dummy_hcd: prevent fifo_req reuse during giveback","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: dummy_hcd: prevent fifo_req reuse during giveback\n\ndummy_hcd embeds a single shared usb_request (dum->fifo_req) that the\n\"emulated single-request FIFO\" fast-path in dummy_queue() reuses for\nsmall IN transfers: it copies the caller's request into it\n(req->req = *_req) and queues it, treating list_empty(&fifo_req.queue)\nas \"the slot is free\".\n\nThe completion side (dummy_timer/transfer/nuke/dummy_dequeue) follows\nthe standard pattern: list_del_init(&req->queue) unlinks the request,\nthen the lock is dropped and usb_gadget_giveback_request() invokes\nreq->complete().  But list_del_init() makes fifo_req.queue look empty\n*before* the completion callback returns, so a concurrent dummy_queue()\non another CPU sees the slot as free, reuses fifo_req and runs\nreq->req = *_req -- overwriting req->complete while dummy_timer is\nmid-calling it.  The indirect call then jumps to a clobbered pointer,\ncausing a general protection fault / page fault in dummy_timer\n(syzkaller extid faf3a6cf579fc65591ca).  The clobbering write is an\nin-bounds memcpy on a live shared object, so KASAN cannot flag it.\n\nAdd a fifo_req_busy bit covering the shared request's whole lifetime:\nset it in dummy_queue() when the FIFO fast-path takes fifo_req (making\nit the fast-path guard, replacing the list_empty(&fifo_req.queue)\ntest), and clear it after the completion callback has returned, via a\ndummy_giveback() helper used at all four gadget-request giveback\nsites.  The shared slot can no longer be reused until its completion\ncallback has finished.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-10 13:20:29","updated_at":"2026-08-10 13:20:29"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/e24b33618231034bf01dfaff4fd3409d4b4d5b2e","name":"https://git.kernel.org/stable/c/e24b33618231034bf01dfaff4fd3409d4b4d5b2e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e2b2740f1242bc70b5b46da2cdbbaa419f490e59","name":"https://git.kernel.org/stable/c/e2b2740f1242bc70b5b46da2cdbbaa419f490e59","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e239ea91b48180ed48a86ac25643832a02c88456","name":"https://git.kernel.org/stable/c/e239ea91b48180ed48a86ac25643832a02c88456","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/67b589d09a96882d56842dced5698ed8dd06ce45","name":"https://git.kernel.org/stable/c/67b589d09a96882d56842dced5698ed8dd06ce45","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d5e5cd3654d2b5359a12ea6586120f05b28634ee","name":"https://git.kernel.org/stable/c/d5e5cd3654d2b5359a12ea6586120f05b28634ee","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-68370","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68370","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 e2b2740f1242bc70b5b46da2cdbbaa419f490e59 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 67b589d09a96882d56842dced5698ed8dd06ce45 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 e239ea91b48180ed48a86ac25643832a02c88456 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 e24b33618231034bf01dfaff4fd3409d4b4d5b2e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 d5e5cd3654d2b5359a12ea6586120f05b28634ee git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.12","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.12 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.148 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.101 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.42 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.6 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc5 * 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":["drivers/usb/gadget/udc/dummy_hcd.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"e2b2740f1242bc70b5b46da2cdbbaa419f490e59","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"67b589d09a96882d56842dced5698ed8dd06ce45","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"e239ea91b48180ed48a86ac25643832a02c88456","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"e24b33618231034bf01dfaff4fd3409d4b4d5b2e","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"d5e5cd3654d2b5359a12ea6586120f05b28634ee","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/usb/gadget/udc/dummy_hcd.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.12"},{"lessThan":"2.6.12","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.148","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.101","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.42","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc5","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.148","versionStartIncluding":"2.6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.101","versionStartIncluding":"2.6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.42","versionStartIncluding":"2.6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.6","versionStartIncluding":"2.6.12","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc5","versionStartIncluding":"2.6.12","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: dummy_hcd: prevent fifo_req reuse during giveback\n\ndummy_hcd embeds a single shared usb_request (dum->fifo_req) that the\n\"emulated single-request FIFO\" fast-path in dummy_queue() reuses for\nsmall IN transfers: it copies the caller's request into it\n(req->req = *_req) and queues it, treating list_empty(&fifo_req.queue)\nas \"the slot is free\".\n\nThe completion side (dummy_timer/transfer/nuke/dummy_dequeue) follows\nthe standard pattern: list_del_init(&req->queue) unlinks the request,\nthen the lock is dropped and usb_gadget_giveback_request() invokes\nreq->complete().  But list_del_init() makes fifo_req.queue look empty\n*before* the completion callback returns, so a concurrent dummy_queue()\non another CPU sees the slot as free, reuses fifo_req and runs\nreq->req = *_req -- overwriting req->complete while dummy_timer is\nmid-calling it.  The indirect call then jumps to a clobbered pointer,\ncausing a general protection fault / page fault in dummy_timer\n(syzkaller extid faf3a6cf579fc65591ca).  The clobbering write is an\nin-bounds memcpy on a live shared object, so KASAN cannot flag it.\n\nAdd a fifo_req_busy bit covering the shared request's whole lifetime:\nset it in dummy_queue() when the FIFO fast-path takes fifo_req (making\nit the fast-path guard, replacing the list_empty(&fifo_req.queue)\ntest), and clear it after the completion callback has returned, via a\ndummy_giveback() helper used at all four gadget-request giveback\nsites.  The shared slot can no longer be reused until its completion\ncallback has finished."}],"providerMetadata":{"dateUpdated":"2026-08-10T12:03:48.320Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e2b2740f1242bc70b5b46da2cdbbaa419f490e59"},{"url":"https://git.kernel.org/stable/c/67b589d09a96882d56842dced5698ed8dd06ce45"},{"url":"https://git.kernel.org/stable/c/e239ea91b48180ed48a86ac25643832a02c88456"},{"url":"https://git.kernel.org/stable/c/e24b33618231034bf01dfaff4fd3409d4b4d5b2e"},{"url":"https://git.kernel.org/stable/c/d5e5cd3654d2b5359a12ea6586120f05b28634ee"}],"title":"usb: gadget: dummy_hcd: prevent fifo_req reuse during giveback","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-68370","datePublished":"2026-08-10T12:03:48.320Z","dateReserved":"2026-07-30T09:28:09.386Z","dateUpdated":"2026-08-10T12:03:48.320Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-10 13:20:29","lastModifiedDate":"2026-08-10 13:20:29","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"68370","Ordinal":"1","Title":"usb: gadget: dummy_hcd: prevent fifo_req reuse during giveback","CVE":"CVE-2026-68370","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"68370","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: dummy_hcd: prevent fifo_req reuse during giveback\n\ndummy_hcd embeds a single shared usb_request (dum->fifo_req) that the\n\"emulated single-request FIFO\" fast-path in dummy_queue() reuses for\nsmall IN transfers: it copies the caller's request into it\n(req->req = *_req) and queues it, treating list_empty(&fifo_req.queue)\nas \"the slot is free\".\n\nThe completion side (dummy_timer/transfer/nuke/dummy_dequeue) follows\nthe standard pattern: list_del_init(&req->queue) unlinks the request,\nthen the lock is dropped and usb_gadget_giveback_request() invokes\nreq->complete().  But list_del_init() makes fifo_req.queue look empty\n*before* the completion callback returns, so a concurrent dummy_queue()\non another CPU sees the slot as free, reuses fifo_req and runs\nreq->req = *_req -- overwriting req->complete while dummy_timer is\nmid-calling it.  The indirect call then jumps to a clobbered pointer,\ncausing a general protection fault / page fault in dummy_timer\n(syzkaller extid faf3a6cf579fc65591ca).  The clobbering write is an\nin-bounds memcpy on a live shared object, so KASAN cannot flag it.\n\nAdd a fifo_req_busy bit covering the shared request's whole lifetime:\nset it in dummy_queue() when the FIFO fast-path takes fifo_req (making\nit the fast-path guard, replacing the list_empty(&fifo_req.queue)\ntest), and clear it after the completion callback has returned, via a\ndummy_giveback() helper used at all four gadget-request giveback\nsites.  The shared slot can no longer be reused until its completion\ncallback has finished.","Type":"Description","Title":"usb: gadget: dummy_hcd: prevent fifo_req reuse during giveback"}]}}}