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AcrobatApplication · Adobe

CVE-2021-21021

HIGH · 8.8 CVSS v3.1 Published 2021-02-11
Fix available
A fix is available. Upgrade to after 20.013.20074 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by a Use After Free vulnerability. An unauthenticated attacker could leverage this vulnerability to achieve arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Adobe Acrobat Reader DC contains a Use After Free vulnerability that allows an unauthenticated attacker to achieve arbitrary code execution in the context of the current user. Exploitation requires the victim to open a malicious PDF file, making this a social-engineering-dependent attack vector.

MitigationDeploy the patched Adobe Acrobat Reader DC version (2020.013.20075 or later for the 2020 track, newer for other tracks) via endpoint management tools; educate users to avoid opening untrusted PDF files.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AcrobatApplication
Affected:>= 17.0, <= 17.011.30188>= 20.0, <= 20.001.30018
Acrobat DcApplication
Affected:<= 20.013.20074
Acrobat ReaderApplication
Affected:>= 17.0, <= 17.011.30188>= 20.0, <= 20.001.300183
Acrobat Reader DcApplication
Affected:<= 20.013.20074

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Adobe Acrobat or Reader product
    On Windows, open Programs and Features or run: Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*' | Where-Object {$_.DisplayName -like '*Adobe*Acrobat*'}. On macOS, run: system_profiler SPApplications | grep -i acrobat
    Affected if No Adobe Acrobat or Reader is installed, then not affected by this specific vulnerability.
  2. Determine the exact version number
    On Windows, right-click the Adobe Acrobat/Reader shortcut, select Properties, and check the Details tab for Product Version. Alternatively, open Adobe Acrobat/Reader, go to Help > About Adobe Acrobat/Reader to display the exact version string.
    Affected if The version displayed must be compared against the affected ranges.
  3. Compare installed version against affected ranges
    Check if the installed version falls within any of these ranges: Adobe Acrobat/Reader 17.0 through 17.011.30188; Adobe Acrobat/Reader 20.0 through 20.001.30018/300183; Adobe Acrobat/Reader DC through 20.013.20074
    Affected if Installed version is within any of these ranges: 17.0-17.011.30188, 20.0-20.001.30018/300183, or up to 20.013.20074 for DC variants.
  4. Verify PDF handling is enabled
    Confirm the Adobe Acrobat or Reader application can open and process PDF files normally. Check that the PDF file association is registered and the application launches without errors.
    Affected if If PDF processing is functional, the malicious file could be processed and exploitation could occur.

A user is affected if Adobe Acrobat or Reader is installed with a version number within the ranges 17.0-17.011.30188, 20.0-20.001.30018/300183, or up to 20.013.20074 for DC variants, and the application can open PDF files.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 20.013.20074
Interim mitigation

Deploy the patched Adobe Acrobat Reader DC version (2020.013.20075 or later for the 2020 track, newer for other tracks) via endpoint management tools; educate users to avoid opening untrusted PDF files.

Fix this in Acrobat Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,090
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,744.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-21021 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data