CVE-2021-25518

Local code execution via secure_log boundary failure

Published Dec 8, 2021 · Updated Aug 3, 2024

Out-of-bounds write in secure_log on selected Exynos Samsung Mobile Devices before SMR Dec-2021 Release 1 allows local users to execute code. The secure_log routines in BL31 and LDFW apply an improper boundary check, permitting a memory or register write beyond the intended range. Exploitation requires high local privileges and enables arbitrary memory modification and code execution in trusted firmware context.

CVSS severity6.4
Medium
EPSS probability0.11%
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 write in secure_log on selected Exynos Samsung Mobile Devices before SMR Dec-2021 Release 1 allows local users to execute code. The secure_log routines in BL31 and LDFW apply an improper boundary check, permitting a memory or register write beyond the intended range. Exploitation requires high local privileges and enables arbitrary memory modification and code execution in trusted firmware context.

The record

CVE
CVE-2021-25518
Published
Dec 8, 2021
Updated
Aug 3, 2024
Vendor
Samsung Electronics Co., Ltd.
Product
Samsung Mobile Devices
Classifications
CWE-119, CWE-787, T1404
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 8, 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=P(9.0), Q(10.0), R(11.0) devices with selected Exynos chipsets <SMR Dec-2021 Release 1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

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

Published CVSS scores

6.4Samsung MobileCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.6NIST NVDAV: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-787Out-of-bounds Write
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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