CVE-2026-63893

Description

In 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.

References

• https://git.kernel.org/stable/c/01deda0152066c6c955f0619114ea6afa070aaec
• https://git.kernel.org/stable/c/31b98e503ecca8077e5247253dd5425ab84bc96d
• https://git.kernel.org/stable/c/5c06a3043ad944f087bb2ae0aae28d820bb9f460
• https://git.kernel.org/stable/c/6a63623621639acbb39bc2d9fb09559681716695
• https://git.kernel.org/stable/c/8d4a758b407ab3de3be86d1ceadfa35d717d30c7