CVE-2021-28632

Remote code execution via AcroForm field use-after-free

Published Aug 24, 2021 · Updated Sep 16, 2024

Use-after-free in Adobe Acrobat Reader DC 2021.001.20155 and earlier allows remote attackers to execute code via a malicious PDF. The AcroForm.api textSize setter locks a parent CPDField, then recursively processes descendants after a child field has been freed because object existence is not validated. Exploitation requires a victim to open the crafted document, and resulting code runs in the current user's process context.

CVSS severity7.8
High
EPSS probability5.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Adobe Acrobat Reader DC 2021.001.20155 and earlier allows remote attackers to execute code via a malicious PDF. The AcroForm.api textSize setter locks a parent CPDField, then recursively processes descendants after a child field has been freed because object existence is not validated. Exploitation requires a victim to open the crafted document, and resulting code runs in the current user's process context.

The record

CVE
CVE-2021-28632
Published
Aug 24, 2021
Updated
Sep 16, 2024
Vendor
Adobe
Product
Adobe Acrobat Reader
Classifications
CWE-416, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=unspecified <=2017.011.30196
  2. Affected versionversion=unspecified <=2020.001.30025
  3. Affected versionversion=unspecified <=2021.001.20155
  4. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Acrobat Readerversion=unspecified <=2017.011.30196; version=unspecified <=2020.001.30025; version=unspecified <=2021.001.20155; 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
7.8NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
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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