CVE-2025-38556

Kernel crash via zero-bit HID report conversion

Published Aug 19, 2025 · Updated Jun 11, 2026

Out-of-bounds read in the Linux kernel allows local users to crash the system by supplying a malformed HID report with a zero-sized field. The HID-core s32ton() routine shifts a 32-bit quantity by a count derived from report_size without handling a value of zero, triggering a shift-out-of-bounds exception. Reachability requires local access and processing of a device report containing the zero-sized field; the documented consequence is a kernel crash.

CVSS severity7.1
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux kernel allows local users to crash the system by supplying a malformed HID report with a zero-sized field. The HID-core s32ton() routine shifts a 32-bit quantity by a count derived from report_size without handling a value of zero, triggering a shift-out-of-bounds exception. Reachability requires local access and processing of a device report containing the zero-sized field; the documented consequence is a kernel crash.

The record

CVE
CVE-2025-38556
Published
Aug 19, 2025
Updated
Jun 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.20
  2. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <3c86548a20d7bc2861aa4de044991a327bebad1a
  3. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <6cdf6c708717c5c6897d0800a1793e83757c7491
  4. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <810189546cb6c8f36443ed091d91f1f5d2fc2ec7
  5. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <865ad8469fa24de1559f247d9426ab01e5ce3a56
  6. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <8b4a94b1510f6a46ec48494b52ee8f67eb4fc836
  7. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd
  8. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <d3b504146c111548ab60b6ef7aad00bfb1db05a2
  9. Affected versionversion=dde5845a529ff753364a6d1aea61180946270bfa <eeeaba737919bdce9885e2a00ac2912f61a3684d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.20; version=dde5845a529ff753364a6d1aea61180946270bfa <3c86548a20d7bc2861aa4de044991a327bebad1a; version=dde5845a529ff753364a6d1aea61180946270bfa <6cdf6c708717c5c6897d0800a1793e83757c7491; version=dde5845a529ff753364a6d1aea61180946270bfa <810189546cb6c8f36443ed091d91f1f5d2fc2ec7; version=dde5845a529ff753364a6d1aea61180946270bfa <865ad8469fa24de1559f247d9426ab01e5ce3a56; version=dde5845a529ff753364a6d1aea61180946270bfa <8b4a94b1510f6a46ec48494b52ee8f67eb4fc836; version=dde5845a529ff753364a6d1aea61180946270bfa <a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd; version=dde5845a529ff753364a6d1aea61180946270bfa <d3b504146c111548ab60b6ef7aad00bfb1db05a2; version=dde5845a529ff753364a6d1aea61180946270bfa <eeeaba737919bdce9885e2a00ac2912f61a3684d

Published CVSS scores

6.9SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
6.6SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
7.1NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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