CVE-2026-31607

Advisory lineage Upstream: 0 Downstream: 20
Modified
Published: 24 Apr 2026, 14:42
Last modified:20 Jul 2026, 12:04

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.8 CRITICAL
v3.1 (cve.org)
EPSS Score
0.31% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

24 Apr 2026, 14:42
Published
Vulnerability first disclosed
20 Jul 2026, 12:04
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: usbip: validate number_of_packets in usbip_pack_ret_submit() When a USB/IP client receives a RET_SUBMIT response, usbip_pack_ret_submit() unconditionally overwrites urb->number_of_packets from the network PDU. This value is subsequently used as the loop bound in usbip_recv_iso() and usbip_pad_iso() to iterate over urb->iso_frame_desc[], a flexible array whose size was fixed at URB allocation time based on the *original* number_of_packets from the CMD_SUBMIT. A malicious USB/IP server can set number_of_packets in the response to a value larger than what was originally submitted, causing a heap out-of-bounds write when usbip_recv_iso() writes to urb->iso_frame_desc[i] beyond the allocated region. KASAN confirmed this with kernel 7.0.0-rc5: BUG: KASAN: slab-out-of-bounds in usbip_recv_iso+0x46a/0x640 Write of size 4 at addr ffff888106351d40 by task vhci_rx/69 The buggy address is located 0 bytes to the right of allocated 320-byte region [ffff888106351c00, ffff888106351d40) The server side (stub_rx.c) and gadget side (vudc_rx.c) already validate number_of_packets in the CMD_SUBMIT path since commits c6688ef9f297 ("usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input") and b78d830f0049 ("usbip: fix vudc_rx: harden CMD_SUBMIT path to handle malicious input"). The server side validates against USBIP_MAX_ISO_PACKETS because no URB exists yet at that point. On the client side we have the original URB, so we can use the tighter bound: the response must not exceed the original number_of_packets. This mirrors the existing validation of actual_length against transfer_buffer_length in usbip_recv_xbuff(), which checks the response value against the original allocation size. Kelvin Mbogo's series ("usb: usbip: fix integer overflow in usbip_recv_iso()", v2) hardens the receive-side functions themselves; this patch complements that work by catching the bad value at its source -- in usbip_pack_ret_submit() before the overwrite -- and using the tighter per-URB allocation bound rather than the global USBIP_MAX_ISO_PACKETS limit. Fix this by checking rpdu->number_of_packets against urb->number_of_packets in usbip_pack_ret_submit() before the overwrite. On violation, clamp to zero so that usbip_recv_iso() and usbip_pad_iso() safely return early.

CVSS Metrics

  • v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.31%• Percentile: 23%

Techniques & Countermeasures

  • CWE-787•Out-of-bounds Write

    The product writes data past the end, or before the beginning, of the intended buffer.

  • CWE-805•Buffer Access with Incorrect Length Value

    The product uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer.

Affected Systems

  • linux•linux

    ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 8d155e2d1c4102f74f82a2bf9c016164bb0f7384 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 906f16a836de13fe61f49cdce2f66f2dbd14caf4 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ef8ebb1c637b4cfb61a9dd2e013376774ee2033b | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 5e1c4ece08ccdc197177631f111845a2c68eede3 | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < 324262c38438255bf6bdbf6342ca47c0badaab76 | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < 973f2c250289f5bf6cc146b98aa6fdde11fe50d6 | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < ce744264b06b97069b3722511ab355738311fee0 | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < 885c8591784da6314f9aa82fa460ac69f9f79e5f | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < 8d155e2d1c4102f74f82a2bf9c016164bb0f7384 | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < 906f16a836de13fe61f49cdce2f66f2dbd14caf4 | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < ef8ebb1c637b4cfb61a9dd2e013376774ee2033b | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < 5e1c4ece08ccdc197177631f111845a2c68eede3 | ≥ 1325f85fa49f57df034869de430f7c302ae23109, < 2ab833a16a825373aad2ba7d54b572b277e95b71 | d9638d9236eed035a575feddec61d036dacc2676 | ca7d3501b7a287c18b5b470e871d3029b0f4842a | 1ce528277e1a66856ed3f7526c1e3458c0ed4a70 | db898d0c5c493ce4177d5e1d3a953e079a56a24b | 5aa02704b9ee67c5b2ee26d54c5f4eb99e93ba9a | ≥ 2.6.32.37, < 2.6.33 | ≥ 2.6.33.10, < 2.6.34 | ≥ 2.6.34.11, < 2.6.35 | ≥ 2.6.35.13, < 2.6.36 | ≥ 2.6.38.3, < 2.6.39 | 2.6.39

  • linux•linux kernel

    ≥ 2.6.39, < 6.6.136 | ≥ 6.7, < 6.12.83 | ≥ 6.13, < 6.18.24 | ≥ 6.19, < 6.19.14 | ≥ 7.0, < 7.0.1

References (18)