VulnerabilityPublished 19 Jul 2026

CVE-2026-63960: Linux kernel · usb: typec: wcove: don't write past struct pd_message in wcove_read_rx_buffer()

Affects Linux kernelSource GCVE Database

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Not known to be exploited.

Data as of 30 Oct 2026, 15:48 UTC

Severity

High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

A fix has been implemented in the Linux kernel that clamps the copy loop to the size of struct pd_message and ensures only the low byte of each register read is stored, preventing out-of-bounds writes. Users should update to the fixed kernel version once available. No other mitigation steps are indicated by the vendor advisory.

Description

A vulnerability in the Linux kernel's USB Type-C wcove driver allows writing beyond the bounds of a struct pd_message in the wcove_read_rx_buffer() function. This occurs due to improper handling of the RX byte count and the way regmap_read() writes data, potentially causing stack corruption. The issue arises when a malicious port partner sends a 31-byte frame, exceeding the 30-byte struct size, and the code writes four bytes per iteration instead of one, leading to out-of-bounds writes.

Impact

This vulnerability can lead to out-of-bounds memory writes on the kernel stack, potentially causing memory corruption or instability in the kernel. While no active exploitation in the wild is known, a malicious USB Type-C port partner could exploit this to disrupt kernel operation or cause denial of service. There is no direct evidence of privilege escalation or code execution from the provided data.

Summary

The Linux kernel's USB Type-C wcove driver had a flaw in wcove_read_rx_buffer() where it copied data from the PD RX FIFO into a struct pd_message without properly clamping the byte count. The RX byte count field is 5 bits (max 31), but the struct pd_message is only 30 bytes. A malicious device sending a 31-byte frame could cause the loop to write one byte past the struct boundary. Additionally, regmap_read() writes a full unsigned int (4 bytes) per call, but the code treated the destination as a byte pointer, causing up to three zero bytes to be written past the struct on the final iteration. This could corrupt the IRQ thread's stack. The fix clamps the loop to the struct size and reads each register into a local variable before storing only the low byte, preventing out-of-bounds writes regardless of RXINFO.

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 30 Oct 2026, 15:48 UTC

Technical details

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