CVE-2023-21596

Arbitrary code execution via malformed embedded fonts

Published Jan 13, 2023 · Updated Mar 5, 2025

Improper input validation in Adobe InCopy 18.0 and earlier and 17.4 and earlier allows remote attackers to execute code via a malicious file. Embedded-font processing fails to validate user-supplied font data before handling it, producing memory corruption. A victim must open the crafted file or visit a malicious page; successful exploitation runs code in the current process.

CVSS severity7.8
High
EPSS probability0.34%
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 Adobe InCopy 18.0 and earlier and 17.4 and earlier allows remote attackers to execute code via a malicious file. Embedded-font processing fails to validate user-supplied font data before handling it, producing memory corruption. A victim must open the crafted file or visit a malicious page; successful exploitation runs code in the current process.

The record

CVE
CVE-2023-21596
Published
Jan 13, 2023
Updated
Mar 5, 2025
Vendor
Adobe
Product
InCopy
Classifications
CWE-20, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 5, 2025Record 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=unspecified <=17.4
  2. Affected versionversion=unspecified <=18.0
  3. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Adobe · InCopyversion=unspecified <=17.4; version=unspecified <=18.0; version=unspecified <=None

Published CVSS scores

7.8AdobeCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1204.002User Execution: Malicious File
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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