Short USB transfers leak kernel memory in Linux sierra_ms driver
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 7 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel from 2.6.27 is affected. The sierra_ms USB storage driver accepts a short device info transfer, leaving part of a kernel heap buffer uninitialized. An emulated or malicious USB device can cause unprivileged local users to read up to 5 bytes of stale kernel heap memory through the world-readable truinst sysfs attribute, once per read.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
Description from the CNA
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.27 and later | 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.27 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 Patch available CNA
Remediation
Upgrade the Linux kernel to 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10 or 7.3, matching your kernel branch. Red Hat lists no fix planned for Red Hat Enterprise Linux 6 and no fix available for Red Hat Enterprise Linux 7, 8, 9 and 10 and OpenShift Container Platform 4 and 5.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98771
- 2026-10-18 Alias added: GHSA-7hw4-87pj-mc7h
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@4faaad69f18332246bbd4ca41718beb2a305bb72, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-23 Affected versions changed · Red Hat
- 2026-10-23 CVSS score added · Red Hat
- 2026-10-30 Fix available: Linux/Linux@353ca2623104a3baf5642c3ea31569df04ce4aaf, Linux/Linux@411da2ec8c62bfa39407e5a20d659b973b3cf311, Linux/[email protected] +3 · CNA
- 2026-10-30 3 new references · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 8
- 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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Sources
- CVE-2026-98771 · CVE Program
- CVE-2026-98771 · NVD
- FIRST EPSS
- GHSA-7hw4-87pj-mc7h · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98771 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences