Out-of-bounds Read Affecting rv package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL10-RV-18509406
- published3 Aug 2026
- disclosed25 Jul 2026
Introduced: 25 Jul 2026
NewCVE-2026-64339 (opens in a new tab)How to fix?
There is no fixed version for RHEL:10 rv.
NVD Description
Note: Versions mentioned in the description apply only to the upstream rv package and not the rv package as distributed by RHEL.
See How to fix? for RHEL: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.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=2507229
- https://access.redhat.com/security/cve/CVE-2026-64339
- https://git.kernel.org/stable/c/48394f94211cf8fe0ea8604fc441633abf90fc94
- https://git.kernel.org/stable/c/8c6314489550fa81d41723a0ff33f655b5b6c7b6
- https://git.kernel.org/stable/c/fc1b546973c1442d5b947fcdd03581f20ecc5bd2