CVE-2026-31622

/// Technical description

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

NFC: digital: Bounds check NFC-A cascade depth in SDD response handler

The NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3

or 4 bytes to target->nfcid1 on each round, but the number of cascade

rounds is controlled entirely by the peer device. The peer sets the

cascade tag in the SDD_RES (deciding 3 vs 4 bytes) and the

cascade-incomplete bit in the SEL_RES (deciding whether another round

follows).

ISO 14443-3 limits NFC-A to three cascade levels and target->nfcid1 is

sized accordingly (NFC_NFCID1_MAXSIZE = 10), but nothing in the driver

actually enforces this. This means a malicious peer can keep the

cascade running, writing past the heap-allocated nfc_target with each

round.

Fix this by rejecting the response when the accumulated UID would exceed

the buffer.

Commit e329e71013c9 ("NFC: nci: Bounds check struct nfc_target arrays")

fixed similar missing checks against the same field on the NCI p

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References