CVE-2026-98771 affecting package kernel 6.6.157.1-1
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.
- Products
- kernel
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-98771
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 17:25 UTC · Revision 1
Source evidence
CVE-2026-98771 affecting package kernel 6.6.157.1-1
core-osv · Original sourcePublished 18 Oct 2026, 16:17 UTC
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.
osv:AZL-109214
kernel
Fixed versions: Not specified
Complete source record
{
"id": "45a342769e83162d037bb417f5f246d3b86d06e72b4ab3cc982a75dac5462040",
"url": "https://osv.dev/vulnerability/AZL-109214",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2026-98771 affecting package kernel 6.6.157.1-1",
"summary": "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.",
"evidence": "osv:AZL-109214",
"products": [
{
"name": {
"value": "kernel",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": []
}
],
"severity": "unknown",
"structured": {
"id": "AZL-109214",
"aliases": [
"AZL-109214"
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"last_affected": "6.6.157.1-1"
}
]
}
],
"package": {
"name": "kernel",
"purl": "pkg:rpm/azure-linux/kernel",
"ecosystem": "Azure Linux:3"
},
"database_specific": {
"source": "https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-109214.json"
}
}
],
"modified": "2026-10-27T05:36:16Z",
"provider": "osv",
"upstream": [
"CVE-2026-98771"
],
"references": [
"https://nvd.nist.gov/vuln/detail/CVE-2026-98771"
]
},
"related_cves": [
{
"value": "CVE-2026-98771",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 460448,
"published_at": "2026-10-18T16:17:31+00:00"
}