CVE-2026-20989

Physical custom-font use via signature verification bypass

Published Mar 16, 2026 · Updated Mar 16, 2026

Improper signature verification in Samsung Mobile Devices on Android 16 before SMR Mar-2026 Release 1 allows physical attackers to use a custom font. Font Settings accepts a custom font without correctly verifying its cryptographic signature, but Samsung has not disclosed the specific verification error. Exploitation requires physical device access and active user interaction; the documented consequence is unauthorized custom-font use and affected-system integrity modification.

CVSS severity5.1
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

Improper signature verification in Samsung Mobile Devices on Android 16 before SMR Mar-2026 Release 1 allows physical attackers to use a custom font. Font Settings accepts a custom font without correctly verifying its cryptographic signature, but Samsung has not disclosed the specific verification error. Exploitation requires physical device access and active user interaction; the documented consequence is unauthorized custom-font use and affected-system integrity modification.

The record

CVE
CVE-2026-20989
Published
Mar 16, 2026
Updated
Mar 16, 2026
Vendor
Samsung Electronics Co., Ltd.
Product
Samsung Mobile Devices
Classifications
CWE-347
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 16, 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Samsung Electronics Co., Ltd. · Samsung Mobile DevicesAffected versions are unavailable in this record.

Published CVSS scores

2.4NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5.1Samsung MobileCVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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