Medium [CVE-2026-63903] validate interrupt status length
This medium-severity Red Hat Linux advisory covers CVE-2026-63903 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: serial: belkin_sa: validate interrupt status length The Belkin interrupt callback treats interrupt data as a four-byte status report and reads LSR/MSR fields at offsets 2 and 3.
The interrupt-in buffer length is derived from endpoint wMaxPacketSize, and short interrupt transfers may complete successfully with a smaller actual_length.
Check the completed interrupt packet length before parsing status fields so short interrupt endpoints and short successful packets are ignored instead of causing out-of-bounds or stale status-byte reads.
KASAN report as below: BUG: KASAN: slab-out-of-bounds in belkin_sa_read_int_callback() Read of size 1 Call trace: belkin_sa_read_int_callback() (drivers/usb/serial/belkin_sa.c:202) __usb_hcd_giveback_urb() (drivers/usb/core/hcd.c:1630) dummy_timer() (?:?) The driver's interrupt handling routine fails to validate the length of incoming status reports.
This oversight allows a local attacker, by connecting a specially crafted USB device, to trigger an out-of-bounds read. The primary consequence is a system crash, leading to a denial of service.
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 7 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 7 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 7 days ago·verify at source
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