CVE-2023-21287Network attack vector

Remote code execution via mismatched FreeType callbacks

Published Aug 14, 2023 · Updated Oct 9, 2024

Type confusion in Android Framework 11 through 13 allows remote attackers to execute code through maliciously processed font data. FreeType's MetricsVariations service calls size-reset implementations through function pointers with mismatched parameter and return types, invoking undefined behavior during font-driven metric changes. No privileges or user interaction are required, and successful exploitation executes code in the context of the process rendering the crafted font.

CVSS severity9.8
Critical
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Android Framework 11 through 13 allows remote attackers to execute code through maliciously processed font data. FreeType's MetricsVariations service calls size-reset implementations through function pointers with mismatched parameter and return types, invoking undefined behavior during font-driven metric changes. No privileges or user interaction are required, and successful exploitation executes code in the context of the process rendering the crafted font.

The record

CVE
CVE-2023-21287
Published
Aug 14, 2023
Updated
Oct 9, 2024
Vendor
Google
Product
AdMob
Classifications
CWE-843, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 9, 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=11
  2. Affected versionversion=12
  3. Affected versionversion=12l
  4. Affected versionversion=13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google · AdMobversion=11; version=12; version=12l; version=13
Google · Androidversion=11; version=12; version=12L; version=13

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1203Exploitation for Client Execution

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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