CVE-2026-31622: linux kernel Buffer Overflow — Fix

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 path.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0003

Probability of exploitation

0.09%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-120 CWE-120

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.13 — 6.6.136
linux	linux_kernel	6.7 — 6.12.83
linux	linux_kernel	6.13 — 6.18.24
linux	linux_kernel	6.19 — 6.19.14
linux	linux_kernel	7.0 — 7.0.1

References

Advisories & Patches

https://git.kernel.org/stable/c/1bec5698b55aa2be5c3b983dba657c01d0fd3dbc https://git.kernel.org/stable/c/2819f34e08bdffb6f06a51c67948ec5737fb166a https://git.kernel.org/stable/c/46ce8be2ced389bccd84bcc04a12cf2f4d0c22d1 https://git.kernel.org/stable/c/5a59bf70c38ee1eb4be03bab830bbc3a6f0bd1f1 https://git.kernel.org/stable/c/8d9d9bf3565271ca7ab9c716a94e87296177e7ba https://git.kernel.org/stable/c/cc024a3de265ef6c58957f4990eccb9f806208cb

Frequently Asked Questions

What is CVE-2026-31622? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-31622? +

CVE-2026-31622 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0003, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-31622? +

CVE-2026-31622 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-31622? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-31622