# HID: mcp2221: clear rxbuf after I2C/SMBus transfer completes

CVE record · `CVE-2026-89622`

- **Identifiers:** `CVE-2026-89622`
- **State:** Confirmed
- **Severity:** CVSS 7.8 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 11 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 11 Sept 2026, 19:45 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `67a95c21463d066060b0f66d65a75d45bb386ffb to before 198bf4a226229e36dfe254493a45c71c3ffc7e57` (git)
  - affected: `67a95c21463d066060b0f66d65a75d45bb386ffb to before bd146a8ff107c6d77e75597decbcd1df0d7900d6` (git)
  - affected: `67a95c21463d066060b0f66d65a75d45bb386ffb to before d6c6b293173c0ea87189501cbd77e8fa677814a1` (git)
  - affected: `67a95c21463d066060b0f66d65a75d45bb386ffb to before 03c34309eb1bce1b3b5f7c4a94b703f419120383` (git)
  - affected: `67a95c21463d066060b0f66d65a75d45bb386ffb to before 968546b676d992dd1da3e057d40598231f725996` (git)
  - affected: `67a95c21463d066060b0f66d65a75d45bb386ffb to before db2333f88729c8aae062cb171ed058725ff5c901` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.7`
  - unaffected: `before 5.7` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.111 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.51 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.4 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Linux kernel versions from 5.7 up to the fixed releases in the affected ranges are vulnerable to a write use-after-free in the HID mcp2221 driver. The driver keeps a pointer to a caller's buffer after an I2C/SMBus read ends, so a delayed or spurious device report can write into freed memory. The source does not say what an attacker can achieve beyond that, nor what access is needed to trigger it. Upgrade to a fixed kernel release for your branch: 6.1.191 or later, 6.6.160 or later, 6.12.111 or later, or 6.18.51 or later.

Written 12 Nov 2026.

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 7.8 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0016, the 5th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 11 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89622](https://www.cve.org/CVERecord?id=CVE-2026-89622)
- [NVD: CVE-2026-89622](https://nvd.nist.gov/vuln/detail/CVE-2026-89622)

### References from the CNA

- <https://git.kernel.org/stable/c/198bf4a226229e36dfe254493a45c71c3ffc7e57>
- <https://git.kernel.org/stable/c/bd146a8ff107c6d77e75597decbcd1df0d7900d6>
- <https://git.kernel.org/stable/c/d6c6b293173c0ea87189501cbd77e8fa677814a1>
- <https://git.kernel.org/stable/c/03c34309eb1bce1b3b5f7c4a94b703f419120383>
- <https://git.kernel.org/stable/c/968546b676d992dd1da3e057d40598231f725996>
- <https://git.kernel.org/stable/c/db2333f88729c8aae062cb171ed058725ff5c901>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-89622>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89622/>. Everything for agents: <https://agentprime.io/llms.txt>.