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CVE-2026-89621

UnknownEPSS 0.21%

Last modified

CVE-2026-89621 is a vulnerability of currently unknown severity. 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.. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

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.

Metrics

EPSS Probability
0.21%

11.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 67a95c21463d066060b0f66d65a75d45bb386ffb, < cb38b1f149b7143355b37e86c841acf0076e5c2a; >= 67a95c21463d066060b0f66d65a75d45bb386ffb, < b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d; >= 67a95c21463d066060b0f66d65a75d45bb386ffb, < fffcfa367072628c3144cca17d2a3c3c9e50c057; >= 67a95c21463d066060b0f66d65a75d45bb386ffb, < c1c508e8923911cb458234997e55b7a4b9aa066f; >= 67a95c21463d066060b0f66d65a75d45bb386ffb, < bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149; >= 67a95c21463d066060b0f66d65a75d45bb386ffb, < 127de5919820f88a9d55e8371ad4ac49f625f4c5; >= 67a95c21463d066060b0f66d65a75d45bb386ffb, < 7c18fb36708a97ff6772825cc087b6d537bbf0d5; >= 67a95c21463d066060b0f66d65a75d45bb386ffb, < 2c9a6998c19503626c57a2267bf279e204113079
LinuxLinux5.7

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89621?
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.
How severe is CVE-2026-89621?
Severity scoring for CVE-2026-89621 is pending analysis. The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-89621?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST