{"api_version":"1","generated_at":"2026-07-24T20:57:17+00:00","cve":"CVE-2026-63896","urls":{"html":"https://cve.report/CVE-2026-63896","api":"https://cve.report/api/cve/CVE-2026-63896.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63896","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63896"},"summary":{"title":"usb: gadget: composite: fix integer underflow in WebUSB GET_URL handling","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: composite: fix integer underflow in WebUSB GET_URL handling\n\nThe WebUSB GET_URL handler in composite_setup() narrows\nlanding_page_length to fit the host-supplied wLength using\n\n\tlanding_page_length = w_length\n\t\t- WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset;\n\nIf wLength is smaller than WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH the\nunsigned subtraction wraps, and the subsequent\n\n\tmemcpy(url_descriptor->URL,\n\t       cdev->landing_page + landing_page_offset,\n\t       landing_page_length - landing_page_offset);\n\nends up copying close to UINT_MAX bytes from cdev->landing_page into\ncdev->req->buf.  KASAN reports a slab-out-of-bounds in composite_setup\non the kmalloc-2k gadget_info allocation, and FORTIFY_SOURCE traps the\nmemcpy as a 4294967293-byte field-spanning write into\nurl_descriptor->URL (size 252).\n\nA USB host can reach this from a single SETUP packet against any\ngadget that has webusb/use=1 and a landingPage configured.\n\nHandle the small-wLength case before the math: when the host requested\nfewer bytes than the URL descriptor header, only the header is\nmeaningful and no URL bytes need to be copied.  Setting\nlanding_page_length to landing_page_offset makes the existing memcpy a\nno-op and leaves the descriptor returned to the host unchanged for all\nlarger wLength values.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:07","updated_at":"2026-07-19 16:17:07"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/f5869dfaa89854dcf34121036294d42d6c7acb8f","name":"https://git.kernel.org/stable/c/f5869dfaa89854dcf34121036294d42d6c7acb8f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6c5dbc104dadd79fc2923497c20bae759a18758c","name":"https://git.kernel.org/stable/c/6c5dbc104dadd79fc2923497c20bae759a18758c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f8f5a8f48c7cae3fac85e04b593bd47939f9725f","name":"https://git.kernel.org/stable/c/f8f5a8f48c7cae3fac85e04b593bd47939f9725f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a20f0ccf45708af6e063c7234c215d364b00de25","name":"https://git.kernel.org/stable/c/a20f0ccf45708af6e063c7234c215d364b00de25","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/046870ff6b6f7b743c953c061043a9b30700d491","name":"https://git.kernel.org/stable/c/046870ff6b6f7b743c953c061043a9b30700d491","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63896","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63896","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 93c473948c588978cd55d9a3adad8b3e8057aa21 046870ff6b6f7b743c953c061043a9b30700d491 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 93c473948c588978cd55d9a3adad8b3e8057aa21 f5869dfaa89854dcf34121036294d42d6c7acb8f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 93c473948c588978cd55d9a3adad8b3e8057aa21 f8f5a8f48c7cae3fac85e04b593bd47939f9725f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 93c473948c588978cd55d9a3adad8b3e8057aa21 a20f0ccf45708af6e063c7234c215d364b00de25 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 93c473948c588978cd55d9a3adad8b3e8057aa21 6c5dbc104dadd79fc2923497c20bae759a18758c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.3","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.3 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.143 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.93 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.35 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.12 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"63896","cve":"CVE-2026-63896","epss":"0.002000000","percentile":"0.100180000","score_date":"2026-07-20","updated_at":"2026-07-21 00:13:14"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/usb/gadget/composite.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"046870ff6b6f7b743c953c061043a9b30700d491","status":"affected","version":"93c473948c588978cd55d9a3adad8b3e8057aa21","versionType":"git"},{"lessThan":"f5869dfaa89854dcf34121036294d42d6c7acb8f","status":"affected","version":"93c473948c588978cd55d9a3adad8b3e8057aa21","versionType":"git"},{"lessThan":"f8f5a8f48c7cae3fac85e04b593bd47939f9725f","status":"affected","version":"93c473948c588978cd55d9a3adad8b3e8057aa21","versionType":"git"},{"lessThan":"a20f0ccf45708af6e063c7234c215d364b00de25","status":"affected","version":"93c473948c588978cd55d9a3adad8b3e8057aa21","versionType":"git"},{"lessThan":"6c5dbc104dadd79fc2923497c20bae759a18758c","status":"affected","version":"93c473948c588978cd55d9a3adad8b3e8057aa21","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/usb/gadget/composite.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.3"},{"lessThan":"6.3","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.143","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":"6.6.143","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.93","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.35","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.12","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.3","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: composite: fix integer underflow in WebUSB GET_URL handling\n\nThe WebUSB GET_URL handler in composite_setup() narrows\nlanding_page_length to fit the host-supplied wLength using\n\n\tlanding_page_length = w_length\n\t\t- WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset;\n\nIf wLength is smaller than WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH the\nunsigned subtraction wraps, and the subsequent\n\n\tmemcpy(url_descriptor->URL,\n\t       cdev->landing_page + landing_page_offset,\n\t       landing_page_length - landing_page_offset);\n\nends up copying close to UINT_MAX bytes from cdev->landing_page into\ncdev->req->buf.  KASAN reports a slab-out-of-bounds in composite_setup\non the kmalloc-2k gadget_info allocation, and FORTIFY_SOURCE traps the\nmemcpy as a 4294967293-byte field-spanning write into\nurl_descriptor->URL (size 252).\n\nA USB host can reach this from a single SETUP packet against any\ngadget that has webusb/use=1 and a landingPage configured.\n\nHandle the small-wLength case before the math: when the host requested\nfewer bytes than the URL descriptor header, only the header is\nmeaningful and no URL bytes need to be copied.  Setting\nlanding_page_length to landing_page_offset makes the existing memcpy a\nno-op and leaves the descriptor returned to the host unchanged for all\nlarger wLength values."}],"providerMetadata":{"dateUpdated":"2026-07-19T14:55:06.152Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/046870ff6b6f7b743c953c061043a9b30700d491"},{"url":"https://git.kernel.org/stable/c/f5869dfaa89854dcf34121036294d42d6c7acb8f"},{"url":"https://git.kernel.org/stable/c/f8f5a8f48c7cae3fac85e04b593bd47939f9725f"},{"url":"https://git.kernel.org/stable/c/a20f0ccf45708af6e063c7234c215d364b00de25"},{"url":"https://git.kernel.org/stable/c/6c5dbc104dadd79fc2923497c20bae759a18758c"}],"title":"usb: gadget: composite: fix integer underflow in WebUSB GET_URL handling","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63896","datePublished":"2026-07-19T14:55:06.152Z","dateReserved":"2026-07-19T07:54:57.019Z","dateUpdated":"2026-07-19T14:55:06.152Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:07","lastModifiedDate":"2026-07-19 16:17:07","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63896","Ordinal":"1","Title":"usb: gadget: composite: fix integer underflow in WebUSB GET_URL ","CVE":"CVE-2026-63896","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63896","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: composite: fix integer underflow in WebUSB GET_URL handling\n\nThe WebUSB GET_URL handler in composite_setup() narrows\nlanding_page_length to fit the host-supplied wLength using\n\n\tlanding_page_length = w_length\n\t\t- WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset;\n\nIf wLength is smaller than WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH the\nunsigned subtraction wraps, and the subsequent\n\n\tmemcpy(url_descriptor->URL,\n\t       cdev->landing_page + landing_page_offset,\n\t       landing_page_length - landing_page_offset);\n\nends up copying close to UINT_MAX bytes from cdev->landing_page into\ncdev->req->buf.  KASAN reports a slab-out-of-bounds in composite_setup\non the kmalloc-2k gadget_info allocation, and FORTIFY_SOURCE traps the\nmemcpy as a 4294967293-byte field-spanning write into\nurl_descriptor->URL (size 252).\n\nA USB host can reach this from a single SETUP packet against any\ngadget that has webusb/use=1 and a landingPage configured.\n\nHandle the small-wLength case before the math: when the host requested\nfewer bytes than the URL descriptor header, only the header is\nmeaningful and no URL bytes need to be copied.  Setting\nlanding_page_length to landing_page_offset makes the existing memcpy a\nno-op and leaves the descriptor returned to the host unchanged for all\nlarger wLength values.","Type":"Description","Title":"usb: gadget: composite: fix integer underflow in WebUSB GET_URL "}]}}}