CVE-2026-63896

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63896", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.019Z", "datePublished": "2026-07-19T14:55:06.152Z", "dateUpdated": "2026-07-19T14:55:06.152Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-07-19T14:55:06.152Z"}, "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."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/usb/gadget/composite.c"], "versions": [{"version": "93c473948c588978cd55d9a3adad8b3e8057aa21", "lessThan": "046870ff6b6f7b743c953c061043a9b30700d491", "status": "affected", "versionType": "git"}, {"version": "93c473948c588978cd55d9a3adad8b3e8057aa21", "lessThan": "f5869dfaa89854dcf34121036294d42d6c7acb8f", "status": "affected", "versionType": "git"}, {"version": "93c473948c588978cd55d9a3adad8b3e8057aa21", "lessThan": "f8f5a8f48c7cae3fac85e04b593bd47939f9725f", "status": "affected", "versionType": "git"}, {"version": "93c473948c588978cd55d9a3adad8b3e8057aa21", "lessThan": "a20f0ccf45708af6e063c7234c215d364b00de25", "status": "affected", "versionType": "git"}, {"version": "93c473948c588978cd55d9a3adad8b3e8057aa21", "lessThan": "6c5dbc104dadd79fc2923497c20bae759a18758c", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/usb/gadget/composite.c"], "versions": [{"version": "6.3", "status": "affected"}, {"version": "0", "lessThan": "6.3", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.6.143"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.12.93"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "6.18.35"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.0.12"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.3", "versionEndExcluding": "7.1"}]}]}], "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"}}}}

{}

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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."}], "id": "CVE-2026-63896", "lastModified": "2026-11-12T15:02:22.670", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2026-07-19T16:17:07.130", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/046870ff6b6f7b743c953c061043a9b30700d491"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/6c5dbc104dadd79fc2923497c20bae759a18758c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/a20f0ccf45708af6e063c7234c215d364b00de25"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f5869dfaa89854dcf34121036294d42d6c7acb8f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f8f5a8f48c7cae3fac85e04b593bd47939f9725f"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-190"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: usb: gadget: composite: fix integer underflow in WebUSB GET_URL handling", "id": "2502467", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502467"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nusb: gadget: composite: fix integer underflow in WebUSB GET_URL handling\nThe WebUSB GET_URL handler in composite_setup() narrows\nlanding_page_length to fit the host-supplied wLength using\nlanding_page_length = w_length\n- WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH + landing_page_offset;\nIf wLength is smaller than WEBUSB_URL_DESCRIPTOR_HEADER_LENGTH the\nunsigned subtraction wraps, and the subsequent\nmemcpy(url_descriptor->URL,\ncdev->landing_page + landing_page_offset,\nlanding_page_length - landing_page_offset);\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).\nA USB host can reach this from a single SETUP packet against any\ngadget that has webusb/use=1 and a landingPage configured.\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.", "A flaw was found in the Linux kernel's USB gadget composite driver. A remote attacker, acting as a malicious USB host, could send a specially crafted `GET_URL` request. This request, with a small `wLength` value, triggers an integer underflow when calculating the buffer length for a memory copy operation. This leads to an out-of-bounds write, causing memory corruption and potentially a denial of service or arbitrary code execution."], "name": "CVE-2026-63896", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63896\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63896\nhttps://lore.kernel.org/linux-cve-announce/2026071942-CVE-2026-63896-6fb2@gregkh/T"], "threat_severity": "Moderate"}

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