Bug 2461459 (CVE-2026-31622) - CVE-2026-31622 kernel: NFC: digital: Bounds check NFC-A cascade depth in SDD response handler
Summary: CVE-2026-31622 kernel: NFC: digital: Bounds check NFC-A cascade depth in SDD ...
Keywords:
Status: NEW
Alias: CVE-2026-31622
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-24 15:02 UTC by OSIDB Bzimport
Modified: 2026-04-24 20:22 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-04-24 15:02:41 UTC
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.


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