CVE-2021-28550Known exploitationNetwork attack vector

Current-user code execution via use-after-free

Published Sep 2, 2021 · Updated Oct 21, 2025

Use-after-free in Adobe Acrobat Reader DC allows remote attackers to execute arbitrary code as the current user through a malicious PDF file. Adobe identifies the memory-lifetime error but has not disclosed the affected parser, object, or stale-reference operation. A victim must open the file; affected releases include Continuous 2021.001.20150 and earlier, Classic 2020 2020.001.30020 and earlier, and Classic 2017 2017.011.30194 and earlier.

CVSS severity9.6
Critical
EPSS probability52.01%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Adobe Acrobat Reader DC allows remote attackers to execute arbitrary code as the current user through a malicious PDF file. Adobe identifies the memory-lifetime error but has not disclosed the affected parser, object, or stale-reference operation. A victim must open the file; affected releases include Continuous 2021.001.20150 and earlier, Classic 2020 2020.001.30020 and earlier, and Classic 2017 2017.011.30194 and earlier.

The record

CVE
CVE-2021-28550
Published
Sep 2, 2021
Updated
Oct 21, 2025
Vendor
Adobe
Product
Adobe Acrobat Reader
Classifications
CWE-416, T1204.002, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 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 <=2017.011.30194
  2. Affected versionversion=unspecified <=2020.001.30020
  3. Affected versionversion=unspecified <=2021.001.20150
  4. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Acrobat Readerversion=unspecified <=2017.011.30194; version=unspecified <=2020.001.30020; version=unspecified <=2021.001.20150; version=unspecified <=None

Published CVSS scores

9.6AdobeCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
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.

Reported exploitation

Technologies

Your stack

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Your stack

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