CVE-2021-21098Network attack vector

Current-user code execution via PCX out-of-bounds write

Published Jun 28, 2021 · Updated Apr 23, 2025

Out-of-bounds write in Adobe InDesign 16.1 and earlier allows remote attackers to execute code via a crafted PCX file. The PCX parser fails to validate user-supplied data before writing past the end of an allocated structure. Exploitation requires a victim to open the malicious file or visit a page that delivers it, and code runs in the current user's context.

CVSS severity8.8
High
EPSS probability5.75%
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 Adobe InDesign 16.1 and earlier allows remote attackers to execute code via a crafted PCX file. The PCX parser fails to validate user-supplied data before writing past the end of an allocated structure. Exploitation requires a victim to open the malicious file or visit a page that delivers it, and code runs in the current user's context.

The record

CVE
CVE-2021-21098
Published
Jun 28, 2021
Updated
Apr 23, 2025
Vendor
Adobe
Product
InDesign
Classifications
CWE-787, T1203, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 28, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 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 <=16.0
  2. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Adobe · InDesignversion=unspecified <=16.0; version=unspecified <=None

Published CVSS scores

7.8Trend Micro Zero Day InitiativeCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8Adobe Systems IncorporatedCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.3NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:C/I:C/A:C

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-787Out-of-bounds Write
T1203Exploitation for Client Execution
T1204.002User Execution: Malicious File

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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