CVE-2026-63893

In the Linux kernel, the following vulnerability has been resolved:

thunderbolt: property: Reject u32 wrap in tbpropertyentry_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 > blocklen check. tbpropertyparse() then passes entry->value to parsedwdata() 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->devicename / xd->vendorname and is readable back via the per-XDomain devicename / vendorname 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 checkaddoverflow() so a wrapped sum is rejected.