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Acrobat DcApplication · Adobe

CVE-2021-28638

HIGH · 7.8 CVSS v3.1 Published 2021-08-20
Fix available
A fix is available. Upgrade to after 21.005.20054 or later.
See remediation →
81/100
Remediation priority · High
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 2021.005.20054 (and earlier), 2020.004.30005 (and earlier) and 2017.011.30197 (and earlier) are affected by a Heap-based Buffer overflow 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

Heap-based buffer overflow vulnerability in Adobe Acrobat Reader DC allows arbitrary code execution when a victim opens a specially crafted malicious PDF file. The attacker does not require authentication but relies on user interaction (opening the file) to trigger the overflow and achieve code execution in the context of the current user.

MitigationUpdate Adobe Acrobat Reader DC to a patched version beyond 2021.005.20054, 2020.004.30005, or 2017.011.30197. Additionally, educate users to avoid opening untrusted PDF files from unknown sources.

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
Acrobat DcApplication
Affected:>= 15.008.20082, <= 21.005.20054>= 17.011.30059, <= 17.011.30197>= 20.001.30005, <= 20.004.30005
Acrobat Reader DcApplication
Affected:>= 15.008.20082, <= 21.005.20054>= 17.011.30059, <= 17.011.30197>= 20.001.30005, <= 20.004.30005

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
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/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 Reader DC version
    On Windows, open Registry Editor and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\Acrobat Reader\DC\Install. Check the "Version" value. On macOS, right-click the Adobe Acrobat Reader app in /Applications, select Get Info, and note the version number.
    Affected if The version matches one of the affected ranges: 15.008.20082 through 21.005.20054, 17.011.30059 through 17.011.30197, or 20.001.30005 through 20.004.30005.
  2. Confirm product is Acrobat Reader DC (not a different Adobe product)
    Check the registry key path or application name. Ensure the product is specifically "Acrobat Reader DC" or "Adobe Acrobat Reader DC" and not Adobe Acrobat Pro or a different product line.
    Affected if The installed product is Adobe Acrobat Reader DC and the version falls within the affected ranges.
  3. Verify the PDF opening capability exists
    Confirm Adobe Acrobat Reader DC is the default PDF handler or is installed with its full functionality. Check if the application can open and render PDF files normally.
    Affected if The application is fully functional and capable of opening PDF files, which is required for the vulnerability to be triggered.

If Adobe Acrobat Reader DC is installed with a version between 15.008.20082 and 21.005.20054, between 17.011.30059 and 17.011.30197, or between 20.001.30005 and 20.004.30005, the environment is potentially affected.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 21.005.20054
Interim mitigation

Update Adobe Acrobat Reader DC to a patched version beyond 2021.005.20054, 2020.004.30005, or 2017.011.30197. Additionally, educate users to avoid opening untrusted PDF files from unknown sources.

Recommended fix Moderate confidence

Adobe Acrobat Reader DC 2021.006.20034 (or later for 2021 track), 2020.004.30012 (or later for 2020 track), 2020.005.20034 (or later), or 2017.011.30215 (or later for 2017 track)

  1. 1. Close all Adobe Acrobat or Acrobat Reader instances that are currently running
  2. 2. Navigate to the official Adobe download page at https://get.adobe.com/reader/ or use your organization's software distribution channel
  3. 3. Download the latest version of Adobe Acrobat Reader DC for your platform (Windows or macOS)
  4. 4. Run the installer and follow the prompts to complete the installation
  5. 5. Alternatively, use Adobe's official patch updates if available through your organization's patch management system
  6. 6. Verify the installed version by opening Adobe Acrobat/Reader and checking Help > About Adobe Acrobat Reader DC
Caveat Standard Adobe update; minimal risk of breaking changes for typical usage; enterprise deployments should test in staging environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Acrobat Dc Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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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-2021-28638 in production — separate from our analysis above.

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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