CVE-2021-25503

Kernel code execution via legacy HDCP interface

Published Nov 5, 2021 · Updated Aug 3, 2024

Improper input validation in Samsung Mobile Devices before SMR Nov-2021 Release 1 allows local users to execute kernel code. The legacy HDCP kernel interface exposed at /dev/hdcp2 accepts improperly validated input and permits arbitrary read, write, and code execution. Access requires high local privileges on select Android 8.1 through 11 devices with Exynos chipsets, and compromise crosses into the kernel.

CVSS severity5.0
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Samsung Mobile Devices before SMR Nov-2021 Release 1 allows local users to execute kernel code. The legacy HDCP kernel interface exposed at /dev/hdcp2 accepts improperly validated input and permits arbitrary read, write, and code execution. Access requires high local privileges on select Android 8.1 through 11 devices with Exynos chipsets, and compromise crosses into the kernel.

The record

CVE
CVE-2021-25503
Published
Nov 5, 2021
Updated
Aug 3, 2024
Vendor
Samsung Electronics Co., Ltd.
Product
Samsung Mobile Devices
Classifications
CWE-20, T1404
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Nov 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=Select O(8.1), P(9.0), Q(10.0), R(11.0) devices with Exynos chipsets <SMR Nov-2021 Release 1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Samsung Electronics Co., Ltd. · Samsung Mobile Devicesversion=Select O(8.1), P(9.0), Q(10.0), R(11.0) devices with Exynos chipsets <SMR Nov-2021 Release 1

Published CVSS scores

5.0Samsung MobileCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:L
6.7NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1404Exploitation for Privilege Escalation

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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