GHSA-X965-JQ5M-MRM4
Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: property: Reject u32 wrap in tb_property_entry_valid()
entry->value is u32 and entry->length is u16; the sum is performed in u32 and wraps. A malicious XDomain peer can pick value = 0xffffff00, length = 0x100 so the sum 0x100000000 wraps to 0 and passes the > block_len check. tb_property_parse() then passes entry->value to parse_dwdata() as a dword offset into the property block, reading attacker-directed memory far past the allocation.
For TEXT-typed entries with the "deviceid" or "vendorid" keys this lands in xd->device_name / xd->vendor_name and is readable back via the per-XDomain device_name / vendor_name sysfs attributes; the leak is NUL-bounded (kstrdup() stops at the first zero byte) and untargeted (the attacker picks a delta, not an absolute address). DATA-typed entries are parsed into property->value.data but not generically surfaced to userspace.
Use check_add_overflow() so a wrapped sum is rejected.
{
"affected": [],
"aliases": [
"CVE-2026-63893"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T16:17:06Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject u32 wrap in tb_property_entry_valid()\n\nentry-\u003evalue is u32 and entry-\u003elength is u16; the sum is performed in\nu32 and wraps. A malicious XDomain peer can pick\nvalue = 0xffffff00, length = 0x100 so the sum 0x100000000 wraps to 0\nand passes the \u003e block_len check. tb_property_parse() then passes\nentry-\u003evalue to parse_dwdata() as a dword offset into the property\nblock, reading attacker-directed memory far past the allocation.\n\nFor TEXT-typed entries with the \"deviceid\" or \"vendorid\" keys this\nlands in xd-\u003edevice_name / xd-\u003evendor_name and is readable back via\nthe per-XDomain device_name / vendor_name sysfs attributes; the leak\nis NUL-bounded (kstrdup() stops at the first zero byte) and\nuntargeted (the attacker picks a delta, not an absolute address).\nDATA-typed entries are parsed into property-\u003evalue.data but not\ngenerically surfaced to userspace.\n\nUse check_add_overflow() so a wrapped sum is rejected.",
"id": "GHSA-x965-jq5m-mrm4",
"modified": "2026-07-20T15:31:50Z",
"published": "2026-07-19T18:31:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63893"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/01deda0152066c6c955f0619114ea6afa070aaec"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/31b98e503ecca8077e5247253dd5425ab84bc96d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5c06a3043ad944f087bb2ae0aae28d820bb9f460"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6a63623621639acbb39bc2d9fb09559681716695"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8d4a758b407ab3de3be86d1ceadfa35d717d30c7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9fee50c4e1e42f6d3cbe30df584f9f648f626071"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a47784aee77f33f786dc5d7375db821bdae68792"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e8a0b0a93a6ef958e70b1dd4930beb6dc0026b36"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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