Medium [CVE-2026-63904] check URB actual_length for interrupt-IN notifications
This medium-severity Red Hat Linux advisory covers CVE-2026-63904 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
In the Linux kernel, the following vulnerability has been resolved: usb: usbtmc: check URB actual_length for interrupt-IN notifications USBTMC devices can use an optional interrupt endpoint for notification messages.
These typically contain two-byte headers indicating the payload format, but the driver does not check if these headers are present before accessing the data buffers. In cases where the URB actual_length is not enough to fit these headers, the driver will either cause an out-of-bounds read, or consume stale leftover data from a previous notification.
Fix by checking if actual_data contains enough bytes for the headers, otherwise resubmit URB to the interrupt endpoint. A flaw was found in the Linux kernel's USB Test and Measurement Class (USBTMC) driver.
This vulnerability occurs because the driver does not properly verify the size of incoming notification messages, specifically failing to ensure that required two-byte headers are present. An attacker could exploit this by sending malformed USBTMC messages, potentially leading to an out-of-bounds read.
This could result in a system crash (Denial of Service) or the disclosure of sensitive information. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-125.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 6 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 6 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 6 days ago·verify at source
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