# CVE-2026-31622: NFC: digital: Bounds check NFC-A cascade depth in SDD response handler

> A malicious NFC peer can trigger a heap buffer overflow in the Linux kernel NFC driver, potentially leading to code execution or privilege escalation.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Apr 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-83876, BELL-CVE-2026-31622, DEBIAN-CVE-2026-31622, GHSA-3r85-565g-4jhq, ROOT-OS-DEBIAN-11-CVE-2026-31622, ROOT-OS-DEBIAN-12-CVE-2026-31622, ROOT-OS-UBUNTU-2204-CVE-2026-31622, ROOT-OS-UBUNTU-2404-CVE-2026-31622, UBUNTU-CVE-2026-31622

## What is CVE-2026-31622?

CVE-2026-31622 is a high-severity memory corruption vulnerability in Linux kernel, published on 24 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2026-31622?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31622?

Apply the vendor's patch.

## Is CVE-2026-31622 being exploited?

There is no known exploitation of CVE-2026-31622 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31622 and fix it if it is affected.

What it is: CVE-2026-31622 is a high-severity memory corruption vulnerability in Linux kernel, published on 24 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-31622 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-31622/ (Markdown: https://insights.sbomify.com/CVE-2026-31622/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31622
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31622
- OSV: https://osv.dev/vulnerability/CVE-2026-31622

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31622/
Summaries are generated and may contain mistakes; the official description above is the record.