CVE-2026-63960

Published Jul 19, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: usb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer() wcove_read_rx_buffer() copies the PD RX FIFO into the caller's struct pd_message with for (i = 0; i < USBC_RXINFO_RXBYTES(info); i++) regmap_read(wcove->regmap, USBC_RX_DATA + i, msg + i); which has two problems: USBC_RXINFO_RXBYTES() is a 5-bit field (max 31) while struct pd_message is 30 bytes (__le16 header + __le32 payload[PD_MAX_PAYLOAD], packed). The byte count latched in RXINFO is the number of bytes the port partner put on the wire, so a malicious partner that transmits a 31-byte frame can drive the loop one byte past the destination if the WCOVE BMC receiver does not enforce the PD object-count limit in hardware. The existing FIXME flagged this as unverified. Independently, regmap_read() takes an unsigned int * and stores a full unsigned int at the destination. Passing the byte pointer msg + i means each iteration writes four bytes; the high three are zero (val_bits is 8) and are normally overwritten by the next iteration, but the final iteration's high bytes are not. With RXBYTES == 30 the i == 29 iteration already writes three zero bytes past msg, which sits on the IRQ thread's stack in wcove_typec_irq(). Clamp the loop to sizeof(struct pd_message) and read each register into a local before storing only its low byte, so the copy can never exceed the destination regardless of what RXINFO reports.

Is your site exposed to CVE-2026-63960?

Run a free security scan — no signup, results in seconds.

References

Frequently Asked Questions

What is CVE-2026-63960? +
In the Linux kernel, the following vulnerability has been resolved: usb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer() wcove_read_rx_buffer() copies the PD RX FIFO into the caller's struct pd_message with for (i = 0; i < USBC_RXINFO_RXBYTES(info); i++) regmap_read(wcove->regmap, USBC_RX_DATA + i, msg + i); which has two problems: USBC_RXINFO_RXBYTES() is a 5-bit field (max 31) while struct pd_message is 30 bytes (__le16 header + __le32 payload[PD_MAX_PAYLOAD], packed). The byte count latched in RXINFO is the number of bytes the port partner put on the wire, so a malicious partner that transmits a 31-byte frame can drive the loop one byte past the destination if the WCOVE BMC receiver does not enforce the PD object-count limit in hardware. The existing FIXME flagged this as unverified. Independently, regmap_read() takes an unsigned int * and stores a full unsigned int at the destination. Passing the byte pointer msg + i means each iteration writes four bytes; the high three are zero (val_bits is 8) and are normally overwritten by the next iteration, but the final iteration's high bytes are not. With RXBYTES == 30 the i == 29 iteration already writes three zero bytes past msg, which sits on the IRQ thread's stack in wcove_typec_irq(). Clamp the loop to sizeof(struct pd_message) and read each register into a local before storing only its low byte, so the copy can never exceed the destination regardless of what RXINFO reports.
How do I check if I'm vulnerable to CVE-2026-63960? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-63960 — free, no signup required.