CVE-2021-39831

Current-user code execution via PDF parser overwrite

Published Sep 29, 2021 · Updated Apr 23, 2025

Out-of-bounds write in Adobe FrameMaker 2019 Update 8 and earlier and 2020 Release Update 2 and earlier allows local users to execute code via a PDF. The PDF parser writes beyond an allocated buffer while processing crafted file content; Adobe has not disclosed the parser routine or malformed field. Execution requires a victim to open the malicious file and runs with that user's privileges, permitting code execution but not automatic network compromise.

CVSS severity7.8
High
EPSS probability2.17%
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 FrameMaker 2019 Update 8 and earlier and 2020 Release Update 2 and earlier allows local users to execute code via a PDF. The PDF parser writes beyond an allocated buffer while processing crafted file content; Adobe has not disclosed the parser routine or malformed field. Execution requires a victim to open the malicious file and runs with that user's privileges, permitting code execution but not automatic network compromise.

The record

CVE
CVE-2021-39831
Published
Sep 29, 2021
Updated
Apr 23, 2025
Vendor
Adobe
Product
Adobe FrameMaker
Classifications
CWE-787, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=2019.8
  2. Affected versionversion=unspecified <=2020.2
  3. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Adobe · Adobe FrameMakerversion=unspecified <=2019.8; version=unspecified <=2020.2; 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-787Out-of-bounds Write
T1204.002Malicious 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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