VulnerabilityPublished 19 Jul 2026

CVE-2026-63902: Linux kernel · USB: serial: cypress_m8: validate interrupt packet headers

Affects Linux kernelSource GCVE Database

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Not known to be exploited.

Data as of 30 Oct 2026, 15:36 UTC

Severity

Medium

Rated Medium 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 to validate interrupt packet headers before reading them, preventing out-of-bounds access. Users should update to the fixed kernel version once available. No additional mitigation steps are indicated.

Description

A vulnerability in the Linux kernel's USB serial driver for Cypress M8 devices allows out-of-bounds reads due to improper validation of interrupt packet headers. The flaw occurs when malformed short interrupt reports are processed without verifying the header length, leading to potential memory safety issues. The issue has been fixed by adding checks to ensure the packet contains the expected header before reading it, preventing out-of-bounds access.

Impact

This vulnerability can cause out-of-bounds memory reads in the kernel, which may lead to kernel crashes or memory corruption. However, no information about exploitation in the wild or privilege escalation is provided. The impact is limited to potential memory safety issues within the USB serial driver handling Cypress M8 devices.

Summary

The Linux kernel's cypress_m8 USB serial driver parses interrupt-in buffers based on selected Cypress packet formats. Format 1 uses a two-byte status/count header, while format 2 uses a one-byte combined header. The vulnerability arises because the driver does not verify that the completed interrupt packet contains the expected header before reading it. This can lead to out-of-bounds reads when short packets are received and URB_SHORT_NOT_OK is not set. The fix involves validating the header presence and ignoring malformed short reports, resubmitting the interrupt URB to avoid memory safety violations. The issue was detected by KASAN as a slab-out-of-bounds read in cypress_read_int_callback().

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 30 Oct 2026, 15:36 UTC

Technical details

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