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Out-of-bounds Read Affecting kernel-rt-debug-devel package, versions *

Severity

 Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.2% (10th percentile)

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  • Snyk IDSNYK-CENTOS10-KERNELRTDEBUGDEVEL-18509355
  • published3 Aug 2026
  • disclosed25 Jul 2026
Report a new vulnerability Found a mistake?

Introduced: 25 Jul 2026

NewCVE-2026-64339  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-rt-debug-devel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-devel package and not the kernel-rt-debug-devel package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

usb: misc: usbio: bound bulk IN response length to the received transfer

usbio_bulk_msg() copies bpkt_len = le16_to_cpu(bpkt->len) bytes out of the bulk IN buffer (usbio->rxbuf, allocated with size usbio->rxbuf_len) into the caller's buffer. bpkt_len is fully controlled by the device and is only checked against ibuf_len; ibuf_len in turn is checked against usbio->txbuf_len, not against rxbuf_len:

if ((obuf_len > (usbio->txbuf_len - sizeof(*bpkt))) ||
    (ibuf_len > (usbio->txbuf_len - sizeof(*bpkt))))
    return -EMSGSIZE;

txbuf_len and rxbuf_len are taken independently from the bulk OUT and bulk IN endpoint wMaxPacketSize in usbio_probe(). A malicious or malfunctioning device that advertises a large bulk OUT endpoint and a small bulk IN endpoint (e.g. by claiming one of the quirk-free IDs such as the Lattice NX33U, 0x2ac1:0x20cb) therefore makes ibuf_len, and hence the device-supplied bpkt_len, exceed rxbuf_len. memcpy() then reads up to txbuf_len - rxbuf_len bytes past the end of the rxbuf slab object. The over-read bytes are handed back to the i2c layer and on to user space through i2c-dev, disclosing adjacent slab memory; with KASAN this is reported as a slab-out-of-bounds read.

The number of bytes actually received is already known: act equals the URB actual_length and is bounded by rxbuf_len. Reject any response that claims more payload than was received, mirroring the existing "act < sizeof(*bpkt)" check just above.

The control path (usbio_ctrl_msg()) is not affected: it uses a single buffer (ctrlbuf) for both directions, so its analogous copy can never leave the allocation.

Found by code review. The out-of-bounds read was confirmed under AddressSanitizer with a faithful userspace model of usbio_bulk_msg()'s receive path (an rxbuf_len-sized buffer, the same act/ibuf_len/bpkt_len checks and the memcpy). A USB raw-gadget + dummy_hcd reproducer is also available.

CVSS Base Scores

version 3.1