{"id":"CVE-2026-31607","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nusbip: validate number_of_packets in usbip_pack_ret_submit()\n\nWhen a USB/IP client receives a RET_SUBMIT response,\nusbip_pack_ret_submit() unconditionally overwrites\nur…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nusbip: validate number_of_packets in usbip_pack_ret_submit()\n\nWhen a USB/IP client receives a RET_SUBMIT response,\nusbip_pack_ret_submit() unconditionally overwrites\nur…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-787","CWE-805"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 2.6.39, < 6.6.136","linux_kernel >= 6.7, < 6.12.83","linux_kernel >= 6.13, < 6.18.24","linux_kernel >= 6.19, < 6.19.14","linux_kernel >= 7.0, < 7.0.1"],"patched":["linux_kernel 7.0.1"],"published":"2026-04-24","updated":"2026-07-20","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-31607","references":[{"url":"https://git.kernel.org/stable/c/2ab833a16a825373aad2ba7d54b572b277e95b71","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/324262c38438255bf6bdbf6342ca47c0badaab76","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5e1c4ece08ccdc197177631f111845a2c68eede3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/885c8591784da6314f9aa82fa460ac69f9f79e5f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8d155e2d1c4102f74f82a2bf9c016164bb0f7384","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/906f16a836de13fe61f49cdce2f66f2dbd14caf4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/973f2c250289f5bf6cc146b98aa6fdde11fe50d6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ce744264b06b97069b3722511ab355738311fee0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ef8ebb1c637b4cfb61a9dd2e013376774ee2033b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://access.redhat.com/errata/RHSA-2026:19568","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:19569","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:23224","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:24343","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:25095","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:41236","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2026-31607","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2461521","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31607.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}],"tags":["nvd"],"epss":0.00311,"epssPercentile":0.24144,"ingestedAt":"2026-07-20T12:38:40.920Z","slug":"CVE-2026-31607","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nusbip: validate number_of_packets in usbip_pack_ret_submit()\n\nWhen a USB/IP client receives a RET_SUBMIT response,\nusbip_pack_ret_submit() unconditionally overwrites\nurb->number_of_packets from the network PDU. This value is\nsubsequently used as the loop bound in usbip_recv_iso() and\nusbip_pad_iso() to iterate over urb->iso_frame_desc[], a flexible\narray whose size was fixed at URB allocation time based on the\n*original* number_of_packets from the CMD_SUBMIT.\n\nA malicious USB/IP server can set number_of_packets in the response\nto a value larger than what was originally submitted, causing a heap\nout-of-bounds write when usbip_recv_iso() writes to\nurb->iso_frame_desc[i] beyond the allocated region.\n\nKASAN confirmed this with kernel 7.0.0-rc5:\n\n  BUG: KASAN: slab-out-of-bounds in usbip_recv_iso+0x46a/0x640\n  Write of size 4 at addr ffff888106351d40 by task vhci_rx/69\n\n  The buggy address is located 0 bytes to the right of\n   allocated 320-byte region [ffff888106351c00, ffff888106351d40)\n\nThe server side (stub_rx.c) and gadget side (vudc_rx.c) already\nvalidate number_of_packets in the CMD_SUBMIT path since commits\nc6688ef9f297 (\"usbip: fix stub_rx: harden CMD_SUBMIT path to handle\nmalicious input\") and b78d830f0049 (\"usbip: fix vudc_rx: harden\nCMD_SUBMIT path to handle malicious input\"). The server side validates\nagainst USBIP_MAX_ISO_PACKETS because no URB exists yet at that point.\nOn the client side we have the original URB, so we can use the tighter\nbound: the response must not exceed the original number_of_packets.\n\nThis mirrors the existing validation of actual_length against\ntransfer_buffer_length in usbip_recv_xbuff(), which checks the\nresponse value against the original allocation size.\n\nKelvin Mbogo's series (\"usb: usbip: fix integer overflow in\nusbip_recv_iso()\", v2) hardens the receive-side functions themselves;\nthis patch complements that work by catching the bad value at its\nsource -- in usbip_pack_ret_submit() before the overwrite -- and\nusing the tighter per-URB allocation bound rather than the global\nUSBIP_MAX_ISO_PACKETS limit.\n\nFix this by checking rpdu->number_of_packets against\nurb->number_of_packets in usbip_pack_ret_submit() before the\noverwrite. On violation, clamp to zero so that usbip_recv_iso() and\nusbip_pad_iso() safely return early.\n\n## Affected\n\n- `linux_kernel >= 2.6.39, < 6.6.136`\n- `linux_kernel >= 6.7, < 6.12.83`\n- `linux_kernel >= 6.13, < 6.18.24`\n- `linux_kernel >= 6.19, < 6.19.14`\n- `linux_kernel >= 7.0, < 7.0.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.1`","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}