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CVE-2026-89621— HID: mcp2221: validate report size in mcp2221_raw_event()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.7版本存在安全漏洞，该漏洞源于mcp2221_raw_event()未验证传入HID报告的大小，在MCP2221_I2C_GET_DATA路径中信任设备提供的data[3]作为复制长度，可能导致memcpy读取超出HID传输缓冲区中有效报告数据，从而向用户空间泄露未初始化的内核内存。

AI Predicted 5.5 Difficulty: Moderate EPSS 0.22% · P12

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 67a95c21463d066060b0f66d65a75d45bb386ffb< cb38b1f149b7143355b37e86c841acf0076e5c2a affected
67a95c21463d066060b0f66d65a75d45bb386ffb< b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d affected
67a95c21463d066060b0f66d65a75d45bb386ffb< fffcfa367072628c3144cca17d2a3c3c9e50c057 affected
67a95c21463d066060b0f66d65a75d45bb386ffb< c1c508e8923911cb458234997e55b7a4b9aa066f affected
67a95c21463d066060b0f66d65a75d45bb386ffb< bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149 affected
67a95c21463d066060b0f66d65a75d45bb386ffb< 127de5919820f88a9d55e8371ad4ac49f625f4c5 affected
67a95c21463d066060b0f66d65a75d45bb386ffb< 7c18fb36708a97ff6772825cc087b6d537bbf0d5 affected
67a95c21463d066060b0f66d65a75d45bb386ffb< 2c9a6998c19503626c57a2267bf279e204113079 affected
… +10 more rows
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I. Basic Information for CVE-2026-89621

Vulnerability Information
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Vulnerability Title
HID: mcp2221: validate report size in mcp2221_raw_event()
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.7版本存在安全漏洞，该漏洞源于mcp2221_raw_event()未验证传入HID报告的大小，在MCP2221_I2C_GET_DATA路径中信任设备提供的data[3]作为复制长度，可能导致memcpy读取超出HID传输缓冲区中有效报告数据，从而向用户空间泄露未初始化的内核内存。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 67a95c21463d066060b0f66d65a75d45bb386ffb ~ cb38b1f149b7143355b37e86c841acf0076e5c2a -
Linux Linux 5.7 -

II. Public POCs for CVE-2026-89621

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III. Intelligence Information for CVE-2026-89621

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Patches & Fixes for CVE-2026-89621 (8)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89688 9.8 CRITICAL nfsd: drop the stateid, not the stateowner, on seqid_op replay retry
CVE-2026-89656 9.8 CRITICAL libceph: reject buckets with mismatched CRUSH ids
CVE-2026-89655 9.8 CRITICAL ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock
CVE-2026-89658 9.8 CRITICAL NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup
CVE-2026-89660 9.8 CRITICAL NFSD: Prevent client use-after-free during admin state revocation
CVE-2026-89659 9.8 CRITICAL NFSD: Prevent client use-after-free during delegation revoke
CVE-2026-89662 9.8 CRITICAL NFSD: Prevent lock owner use-after-free during client teardown
CVE-2026-89669 9.8 CRITICAL nfsd: initialize copy-notify stateid before publishing it
CVE-2026-89674 9.8 CRITICAL nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
CVE-2026-89675 9.8 CRITICAL nfsd: fix UAF in async copy cancel and shutdown
CVE-2026-89676 9.8 CRITICAL nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
CVE-2026-89677 9.8 CRITICAL nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
CVE-2026-89681 9.8 CRITICAL nfsd: fix layout fence worker double-reference race
CVE-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke
CVE-2026-89703 9.8 CRITICAL nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations
CVE-2026-89479 9.8 CRITICAL sctp: stop processing a packet once its association is deleted
CVE-2026-89478 9.8 CRITICAL sctp: drop a chunk if its transport was removed
CVE-2026-89702 9.8 CRITICAL nfsd: size fh_verify server sockaddr slot by xpt_locallen
CVE-2026-89482 9.8 CRITICAL nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89708 9.8 CRITICAL nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-89621

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