CVE-2026-31622 PUBLISHED

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

Assigner: Linux
Reserved: 09.03.2026 Published: 24.04.2026 Updated: 24.04.2026

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 path.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to 1bec5698b55aa2be5c3b983dba657c01d0fd3dbc (excl.)
  • affected from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to 5a59bf70c38ee1eb4be03bab830bbc3a6f0bd1f1 (excl.)
  • affected from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to 8d9d9bf3565271ca7ab9c716a94e87296177e7ba (excl.)
  • affected from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to cc024a3de265ef6c58957f4990eccb9f806208cb (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • unaffected from 6.12.83 to 6.12.* (incl.)
  • unaffected from 6.18.24 to 6.18.* (incl.)
  • unaffected from 6.19.14 to 6.19.* (incl.)
  • unaffected from 7.0.1 to 7.0.* (incl.)

References