CVE-2026-80823
Received Received - Intake

Buffer Overflow in Linux Kernel NFC ST21NFCA Driver

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: nfc: st21nfca: validate ATR_REQ length against the received frame st21nfca_tm_recv_atr_req() checks that the received ATR_REQ frame is at least ST21NFCA_ATR_REQ_MIN_SIZE and that the self-declared atr_req->length is at least sizeof(struct st21nfca_atr_req), but never checks that atr_req->length does not exceed the actual received length (skb->len). st21nfca_tm_send_atr_res() then trusts the declared length: gb_len = atr_req->length - sizeof(struct st21nfca_atr_req); ... memcpy(atr_res->gbi, atr_req->gbi, gb_len); so an RF peer that sends a short frame but sets atr_req->length larger than the frame makes gb_len exceed the general bytes actually present, and the memcpy reads out of bounds past the received skb. Those bytes are placed in the ATR_RES and sent back to the peer (kernel-memory disclosure to a proximity attacker); a larger declared length is an out-of-bounds read (DoS). Reject frames whose declared length exceeds the received length. The adjacent nfc_tm_activated() path in the same function already derives its general-bytes length from skb->len rather than the declared field. Found by 0sec (https://0sec.ai) using automated source analysis; the missing bound is evident from source. Compile-tested.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-04
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-80823
EUVD
EUVD-2026-71265

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a memory corruption vulnerability in the Linux kernel's NFC (Near Field Communication) subsystem. It occurs when processing ATR_REQ frames where the declared length exceeds the actual received frame size. This leads to an out-of-bounds read when copying data, potentially exposing kernel memory to nearby attackers or causing a system crash.

Detection Guidance

This vulnerability is specific to the Linux kernel's NFC subsystem and requires kernel-level access to detect. It involves improper validation of ATR_REQ frame lengths in the st21nfca driver. No standard network commands can detect this issue directly. You would need to inspect kernel logs for crashes or memory corruption related to NFC operations, or use kernel debugging tools like ftrace or KASAN if enabled.

Impact Analysis

An attacker within NFC range could exploit this to read sensitive kernel memory or crash the system. This could lead to information disclosure or denial of service. Systems using NFC for communication may be particularly at risk.

Compliance Impact

This vulnerability primarily impacts security and data protection compliance rather than directly affecting GDPR or HIPAA. It enables kernel memory disclosure to a proximity attacker and potential denial-of-service, which could lead to unauthorized data exposure. Compliance risks arise if such vulnerabilities are exploited to access sensitive data, potentially violating GDPR's data protection principles or HIPAA's confidentiality requirements.

Mitigation Strategies

Apply the latest Linux kernel security updates from your distribution vendor. If an update is not immediately available, disable the st21nfca NFC driver module (st21nfca) by blacklisting it in your system's module configuration. Monitor vendor advisories for patches addressing this issue in the NFC subsystem.

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