CVE-2026-98481: nfc: port100: reject frames whose declared length exceeds the received data
In the Linux kernel, the following vulnerability has been resolved:
nfc: port100: reject frames whose declared length exceeds the received data
port100recvresponse() passes the URB transfer buffer to port100rxframeisvalid(), which checksums le16tocpu(frame->datalen) bytes of frame->data. datalen is a 16-bit field supplied by the device and is never checked against the number of bytes actually received (urb->actuallength), so a device reporting a datalen larger than the received frame makes port100datachecksum() read out of bounds past the transfer buffer.
Reject a response whose declared frame size does not fit the received length before validating it.
Found by 0sec (https://0sec.ai) using automated source analysis; the missing bound is evident from source. Compile-tested.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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Fixed in 6.6.159.1-1 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
In nfc port100 response handling, reject a response before validation when the declared frame size (datalen) exceeds the received URB length (urb->actual_length).
Event History
Frequently Asked Questions
What must an attacker control to trigger this issue?
An attacker needs a device that can send crafted responses to the Linux kernel's port100 NFC driver. The device must report a declared frame data length larger than the bytes actually received.
What happens when a malformed response is processed?
Before the fix, the driver uses the device-supplied 16-bit data length while calculating a checksum without first confirming that the received transfer buffer contains that many bytes. This can cause an out-of-bounds read past the transfer buffer.
How can I determine whether a system is affected?
Systems using the Linux kernel port100 NFC driver are relevant. Check whether the kernel includes one of the referenced stable commits, which add validation that the declared response size fits within the received length.