CVE-2021-28552

Arbitrary code execution via XFA use-after-free

Published Aug 24, 2021 · Updated Sep 16, 2024

Use-after-free in Adobe Acrobat Reader DC through version 2021.001.20155 and earlier allows remote attackers to execute arbitrary code via a malicious PDF. XFA template handling operates on an object without validating that the object still exists, producing a dangling-object access that can be leveraged for code execution in the current reader process. Exploitation requires a victim to open the malicious file or visit a malicious page; no authentication is required, but user interaction is mandatory.

CVSS severity7.8
High
EPSS probability4.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in Adobe Acrobat Reader DC through version 2021.001.20155 and earlier allows remote attackers to execute arbitrary code via a malicious PDF. XFA template handling operates on an object without validating that the object still exists, producing a dangling-object access that can be leveraged for code execution in the current reader process. Exploitation requires a victim to open the malicious file or visit a malicious page; no authentication is required, but user interaction is mandatory.

The record

CVE
CVE-2021-28552
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

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 <=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

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-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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo