HID: mcp2221: validate report size in mcp2221_raw_event()
Key facts
- Attack vector
- —
- Privileges required
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- User interaction
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- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: HID: mcp2221: validate report size in mcp2221_raw_event() mcp2221_raw_event() never validates the size of incoming HID reports. In the MCP2221_I2C_GET_DATA path it trusts the device-supplied data[3] as the copy length without checking that 4 + data[3] bytes actually exist in the received report. A malicious or misbehaving USB device can send a short report with a large data[3], causing the memcpy to read past the valid report data in the HID transfer buffer and leak uninitialized kernel memory back to userspace through the I2C/SMBus read path. Add a minimum size check at entry and validate that the source range fits within the received report before the copy.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 6 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89621
- 2026-10-03 Alias added: GHSA-55hm-qvfp-55mj
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/cb38b1f149b7143355b37e86c841acf0076e5c2a
- https://git.kernel.org/stable/c/b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d
- https://git.kernel.org/stable/c/fffcfa367072628c3144cca17d2a3c3c9e50c057
- https://git.kernel.org/stable/c/c1c508e8923911cb458234997e55b7a4b9aa066f
- https://git.kernel.org/stable/c/bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149
- https://git.kernel.org/stable/c/127de5919820f88a9d55e8371ad4ac49f625f4c5
- https://git.kernel.org/stable/c/7c18fb36708a97ff6772825cc087b6d537bbf0d5
- https://git.kernel.org/stable/c/2c9a6998c19503626c57a2267bf279e204113079
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- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
Sources
- CVE-2026-89621 · CVE Program
- CVE-2026-89621 · NVD
- FIRST EPSS
- GHSA-55hm-qvfp-55mj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89621 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences