{"id":"CVE-2026-89621","title":"HID: mcp2221: validate report size in mcp2221_raw_event()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nHID: mcp2221: validate report size in mcp2221_raw_event()\n\nmcp2221_raw_event() never validates the size of incoming HID reports.\nIn the MCP2221_I2C_GET_DATA path it tru…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-125"],"vendor":"Linux","product":"Linux","affected":["Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < cb38b1f149b7143355b37e86c841acf0076e5c2a","Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d","Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < fffcfa367072628c3144cca17d2a3c3c9e50c057","Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < c1c508e8923911cb458234997e55b7a4b9aa066f","Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149","Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < 127de5919820f88a9d55e8371ad4ac49f625f4c5","Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < 7c18fb36708a97ff6772825cc087b6d537bbf0d5","Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < 2c9a6998c19503626c57a2267bf279e204113079","Linux 5.7"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:49:53.686Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89621","references":[{"url":"https://git.kernel.org/stable/c/cb38b1f149b7143355b37e86c841acf0076e5c2a"},{"url":"https://git.kernel.org/stable/c/b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d"},{"url":"https://git.kernel.org/stable/c/fffcfa367072628c3144cca17d2a3c3c9e50c057"},{"url":"https://git.kernel.org/stable/c/c1c508e8923911cb458234997e55b7a4b9aa066f"},{"url":"https://git.kernel.org/stable/c/bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149"},{"url":"https://git.kernel.org/stable/c/127de5919820f88a9d55e8371ad4ac49f625f4c5"},{"url":"https://git.kernel.org/stable/c/7c18fb36708a97ff6772825cc087b6d537bbf0d5"},{"url":"https://git.kernel.org/stable/c/2c9a6998c19503626c57a2267bf279e204113079"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89621.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89621"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532406"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89621"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89621"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89621.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.0022,"epssPercentile":0.12451,"ingestedAt":"2026-09-14T15:23:07.450Z","slug":"CVE-2026-89621","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nHID: mcp2221: validate report size in mcp2221_raw_event()\n\nmcp2221_raw_event() never validates the size of incoming HID reports.\nIn the MCP2221_I2C_GET_DATA path it trusts the device-supplied data[3]\nas the copy length without checking that 4 + data[3] bytes actually\nexist in the received report. A malicious or misbehaving USB device can\nsend a short report with a large data[3], causing the memcpy to read\npast the valid report data in the HID transfer buffer and leak\nuninitialized kernel memory back to userspace through the I2C/SMBus\nread path.\n\nAdd a minimum size check at entry and validate that the source range\nfits within the received report before the copy.\n\n## Affected\n\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < cb38b1f149b7143355b37e86c841acf0076e5c2a`\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d`\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < fffcfa367072628c3144cca17d2a3c3c9e50c057`\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < c1c508e8923911cb458234997e55b7a4b9aa066f`\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149`\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < 127de5919820f88a9d55e8371ad4ac49f625f4c5`\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < 7c18fb36708a97ff6772825cc087b6d537bbf0d5`\n- `Linux >= 67a95c21463d066060b0f66d65a75d45bb386ffb < 2c9a6998c19503626c57a2267bf279e204113079`\n- `Linux 5.7`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89621.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":208070,"id":"CVE-2026-89621","ts":1789922704391,"field":"cvss","old":"4.3","new":"5.5"},{"seq":203959,"id":"CVE-2026-89621","ts":1789490230802,"field":"cvss","old":null,"new":"4.3"},{"seq":203958,"id":"CVE-2026-89621","ts":1789490230802,"field":"severity","old":"none","new":"medium"},{"seq":147217,"id":"CVE-2026-89621","ts":1789270201987,"field":"cvss","old":null,"new":"4.3"},{"seq":147216,"id":"CVE-2026-89621","ts":1789270201987,"field":"severity","old":"none","new":"medium"},{"seq":108972,"id":"CVE-2026-89621","ts":1789183729790,"field":"cvss","old":null,"new":"4.3"},{"seq":108971,"id":"CVE-2026-89621","ts":1789183729790,"field":"severity","old":"none","new":"medium"}]}