{"api_version":"1","generated_at":"2026-07-31T21:33:10+00:00","cve":"CVE-2026-64339","urls":{"html":"https://cve.report/CVE-2026-64339","api":"https://cve.report/api/cve/CVE-2026-64339.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64339","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64339"},"summary":{"title":"usb: misc: usbio: bound bulk IN response length to the received transfer","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: misc: usbio: bound bulk IN response length to the received transfer\n\nusbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt->len) bytes out of\nthe bulk IN buffer (usbio->rxbuf, allocated with size usbio->rxbuf_len)\ninto the caller's buffer.  bpkt_len is fully controlled by the device\nand is only checked against ibuf_len; ibuf_len in turn is checked\nagainst usbio->txbuf_len, not against rxbuf_len:\n\n\tif ((obuf_len > (usbio->txbuf_len - sizeof(*bpkt))) ||\n\t    (ibuf_len > (usbio->txbuf_len - sizeof(*bpkt))))\n\t\treturn -EMSGSIZE;\n\ntxbuf_len and rxbuf_len are taken independently from the bulk OUT and\nbulk IN endpoint wMaxPacketSize in usbio_probe().  A malicious or\nmalfunctioning device that advertises a large bulk OUT endpoint and a\nsmall bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such\nas the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and\nhence the device-supplied bpkt_len, exceed rxbuf_len.  memcpy() then\nreads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab\nobject.  The over-read bytes are handed back to the i2c layer and on to\nuser space through i2c-dev, disclosing adjacent slab memory; with KASAN\nthis is reported as a slab-out-of-bounds read.\n\nThe number of bytes actually received is already known: act equals the\nURB actual_length and is bounded by rxbuf_len.  Reject any response\nthat claims more payload than was received, mirroring the existing\n\"act < sizeof(*bpkt)\" check just above.\n\nThe control path (usbio_ctrl_msg()) is not affected: it uses a single\nbuffer (ctrlbuf) for both directions, so its analogous copy can never\nleave the allocation.\n\nFound by code review.  The out-of-bounds read was confirmed under\nAddressSanitizer with a faithful userspace model of usbio_bulk_msg()'s\nreceive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len\nchecks and the memcpy).  A USB raw-gadget + dummy_hcd reproducer is\nalso available.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:15","updated_at":"2026-07-25 10:17:15"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/fc1b546973c1442d5b947fcdd03581f20ecc5bd2","name":"https://git.kernel.org/stable/c/fc1b546973c1442d5b947fcdd03581f20ecc5bd2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8c6314489550fa81d41723a0ff33f655b5b6c7b6","name":"https://git.kernel.org/stable/c/8c6314489550fa81d41723a0ff33f655b5b6c7b6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/48394f94211cf8fe0ea8604fc441633abf90fc94","name":"https://git.kernel.org/stable/c/48394f94211cf8fe0ea8604fc441633abf90fc94","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64339","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64339","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 121a0f839dbb397af5fabb701cea3e9983223e50 48394f94211cf8fe0ea8604fc441633abf90fc94 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 121a0f839dbb397af5fabb701cea3e9983223e50 fc1b546973c1442d5b947fcdd03581f20ecc5bd2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 121a0f839dbb397af5fabb701cea3e9983223e50 8c6314489550fa81d41723a0ff33f655b5b6c7b6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64339","cve":"CVE-2026-64339","epss":"0.001980000","percentile":"0.098900000","score_date":"2026-07-28","updated_at":"2026-07-29 00:05:33"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/usb/misc/usbio.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"48394f94211cf8fe0ea8604fc441633abf90fc94","status":"affected","version":"121a0f839dbb397af5fabb701cea3e9983223e50","versionType":"git"},{"lessThan":"fc1b546973c1442d5b947fcdd03581f20ecc5bd2","status":"affected","version":"121a0f839dbb397af5fabb701cea3e9983223e50","versionType":"git"},{"lessThan":"8c6314489550fa81d41723a0ff33f655b5b6c7b6","status":"affected","version":"121a0f839dbb397af5fabb701cea3e9983223e50","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/usb/misc/usbio.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.18"},{"lessThan":"6.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc3","versionStartIncluding":"6.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: misc: usbio: bound bulk IN response length to the received transfer\n\nusbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt->len) bytes out of\nthe bulk IN buffer (usbio->rxbuf, allocated with size usbio->rxbuf_len)\ninto the caller's buffer.  bpkt_len is fully controlled by the device\nand is only checked against ibuf_len; ibuf_len in turn is checked\nagainst usbio->txbuf_len, not against rxbuf_len:\n\n\tif ((obuf_len > (usbio->txbuf_len - sizeof(*bpkt))) ||\n\t    (ibuf_len > (usbio->txbuf_len - sizeof(*bpkt))))\n\t\treturn -EMSGSIZE;\n\ntxbuf_len and rxbuf_len are taken independently from the bulk OUT and\nbulk IN endpoint wMaxPacketSize in usbio_probe().  A malicious or\nmalfunctioning device that advertises a large bulk OUT endpoint and a\nsmall bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such\nas the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and\nhence the device-supplied bpkt_len, exceed rxbuf_len.  memcpy() then\nreads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab\nobject.  The over-read bytes are handed back to the i2c layer and on to\nuser space through i2c-dev, disclosing adjacent slab memory; with KASAN\nthis is reported as a slab-out-of-bounds read.\n\nThe number of bytes actually received is already known: act equals the\nURB actual_length and is bounded by rxbuf_len.  Reject any response\nthat claims more payload than was received, mirroring the existing\n\"act < sizeof(*bpkt)\" check just above.\n\nThe control path (usbio_ctrl_msg()) is not affected: it uses a single\nbuffer (ctrlbuf) for both directions, so its analogous copy can never\nleave the allocation.\n\nFound by code review.  The out-of-bounds read was confirmed under\nAddressSanitizer with a faithful userspace model of usbio_bulk_msg()'s\nreceive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len\nchecks and the memcpy).  A USB raw-gadget + dummy_hcd reproducer is\nalso available."}],"providerMetadata":{"dateUpdated":"2026-07-25T08:50:03.272Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/48394f94211cf8fe0ea8604fc441633abf90fc94"},{"url":"https://git.kernel.org/stable/c/fc1b546973c1442d5b947fcdd03581f20ecc5bd2"},{"url":"https://git.kernel.org/stable/c/8c6314489550fa81d41723a0ff33f655b5b6c7b6"}],"title":"usb: misc: usbio: bound bulk IN response length to the received transfer","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64339","datePublished":"2026-07-25T08:50:03.272Z","dateReserved":"2026-07-19T15:36:31.781Z","dateUpdated":"2026-07-25T08:50:03.272Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:15","lastModifiedDate":"2026-07-25 10:17:15","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64339","Ordinal":"1","Title":"usb: misc: usbio: bound bulk IN response length to the received ","CVE":"CVE-2026-64339","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64339","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: misc: usbio: bound bulk IN response length to the received transfer\n\nusbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt->len) bytes out of\nthe bulk IN buffer (usbio->rxbuf, allocated with size usbio->rxbuf_len)\ninto the caller's buffer.  bpkt_len is fully controlled by the device\nand is only checked against ibuf_len; ibuf_len in turn is checked\nagainst usbio->txbuf_len, not against rxbuf_len:\n\n\tif ((obuf_len > (usbio->txbuf_len - sizeof(*bpkt))) ||\n\t    (ibuf_len > (usbio->txbuf_len - sizeof(*bpkt))))\n\t\treturn -EMSGSIZE;\n\ntxbuf_len and rxbuf_len are taken independently from the bulk OUT and\nbulk IN endpoint wMaxPacketSize in usbio_probe().  A malicious or\nmalfunctioning device that advertises a large bulk OUT endpoint and a\nsmall bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such\nas the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and\nhence the device-supplied bpkt_len, exceed rxbuf_len.  memcpy() then\nreads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab\nobject.  The over-read bytes are handed back to the i2c layer and on to\nuser space through i2c-dev, disclosing adjacent slab memory; with KASAN\nthis is reported as a slab-out-of-bounds read.\n\nThe number of bytes actually received is already known: act equals the\nURB actual_length and is bounded by rxbuf_len.  Reject any response\nthat claims more payload than was received, mirroring the existing\n\"act < sizeof(*bpkt)\" check just above.\n\nThe control path (usbio_ctrl_msg()) is not affected: it uses a single\nbuffer (ctrlbuf) for both directions, so its analogous copy can never\nleave the allocation.\n\nFound by code review.  The out-of-bounds read was confirmed under\nAddressSanitizer with a faithful userspace model of usbio_bulk_msg()'s\nreceive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len\nchecks and the memcpy).  A USB raw-gadget + dummy_hcd reproducer is\nalso available.","Type":"Description","Title":"usb: misc: usbio: bound bulk IN response length to the received "}]}}}