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PatchSiren cyber security CVE debrief

CVE-2026-63904 Linux CVE debrief

A vulnerability was found in the Linux kernel's USBTMC driver. The driver does not check if the URB actual_length is enough to fit the headers of notification messages, which can cause an out-of-bounds read or consume stale leftover data from a previous notification. This issue affects users of Linux kernel versions with the USBTMC driver. The fix checks if actual_data contains enough bytes for the headers, otherwise resubmits URB to the interrupt endpoint. Affected systems should be updated with the fix, and compensating controls should be reviewed.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-19
Advisory published
2026-07-19
Advisory updated
2026-07-19

Who should care

Users of Linux kernel versions with the USBTMC driver should verify their systems are updated with the fix. This includes operators, platform administrators, vulnerability management teams, and security teams. Affected scope and severity are unclear, but review of compensating controls and monitoring for exception tracking is recommended.

Technical summary

The Linux kernel's USBTMC driver does not check if the URB actual_length is enough to fit the headers of notification messages. This can cause an out-of-bounds read or consume stale leftover data from a previous notification. The fix checks if actual_data contains enough bytes for the headers, otherwise resubmits URB to the interrupt endpoint. This issue is relevant to users of Linux kernel versions with the USBTMC driver. Defenders should verify system updates and review compensating controls.

Defensive priority

Medium

Recommended defensive actions

  • Verify system updates for Linux kernel
  • Check for compensating controls
  • Monitor for exception tracking
  • Review Linux kernel versions and USBTMC driver usage
  • Perform vulnerability management and asset inventory
  • Implement rollback/change windows and source tracking
  • Conduct exposure review and vendor patch guidance

Evidence notes

Evidence is limited to the supplied source corpus. Primary official records indicate a fix was provided. Vendor remediation is known, but affected scope is unclear. Defenders should verify system updates, review compensating controls, and monitor for exception tracking. The CVE record was published on 2026-07-19T16:17:08.130Z and has not been modified since then. Additional review of Linux kernel versions and USBTMC driver usage is recommended.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-19T16:17:08.130Z and has not been modified since then.