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Acrobat DcApplication · Adobe

CVE-2021-28642

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 an Out-of-bounds write 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

This is an out-of-bounds write vulnerability in Adobe Acrobat Reader DC affecting multiple version branches. An unauthenticated attacker can craft a malicious PDF file that, when opened by a victim, triggers an out-of-bounds memory write, enabling arbitrary code execution in the context of the current user.

MitigationUpdate Adobe Acrobat Reader DC to a version newer than 2021.005.20054, 2020.004.30005, or 2017.011.30197. Additionally, warn users against opening PDF files from untrusted sources and consider disabling JavaScript in Acrobat Reader to reduce attack surface.

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 product
    Open Adobe Acrobat Reader DC or Adobe Acrobat DC, then go to Help > About Adobe Acrobat Reader (or About Adobe Acrobat). Alternatively, on Windows check the Programs and Features list or the registry under HKLM\SOFTWARE\Adobe\Adobe Acrobat for the version key.
    Affected if The application name is Adobe Acrobat DC or Adobe Acrobat Reader DC
  2. Determine exact version number
    Note the full version number displayed in the About dialog (e.g., 21.005.20054). Ensure you capture all five digit groups separated by dots.
    Affected if Unable to retrieve a complete version number for comparison
  3. Compare version against affected range 15.x
    If the version starts with 15., check if it is >= 15.008.20082 and <= 21.005.20054. Versions below 15.008.20082 are not in this range.
    Affected if Version is 15.008.20082 or higher but 21.005.20054 or lower
  4. Compare version against affected range 17.x
    If the version starts with 17., check if it is >= 17.011.30059 and <= 17.011.30197.
    Affected if Version falls between 17.011.30059 and 17.011.30197 inclusive
  5. Compare version against affected range 20.x
    If the version starts with 20., check if it is >= 20.001.30005 and <= 20.004.30005.
    Affected if Version falls between 20.001.30005 and 20.004.30005 inclusive

A user is affected if their installed Adobe Acrobat Reader DC or Adobe Acrobat DC version falls within any of the three vulnerable ranges (15.008.20082-21.005.20054, 17.011.30059-17.011.30197, or 20.001.30005-20.004.30005) and they open a maliciously crafted PDF file.

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 version newer than 2021.005.20054, 2020.004.30005, or 2017.011.30197. Additionally, warn users against opening PDF files from untrusted sources and consider disabling JavaScript in Acrobat Reader to reduce attack surface.

Recommended fix High confidence

Upgrade to the latest available Adobe Acrobat/Reader DC version (2021.006.20060 or later for 2021 track, 20.004.30012 or later for 2020 track, 17.011.30210 or later for 2017 track)

  1. 1. Verify current Adobe Acrobat/Reader version by opening the application, clicking Help > About Adobe Acrobat/Reader DC
  2. 2. Close all Adobe applications
  3. 3. Download the latest version from the official Adobe website at get.adobe.com/reader or get.adobe.com/acrobat
  4. 4. Run the installer and follow the prompts to complete the upgrade
  5. 5. Restart the computer after installation completes
  6. 6. Verify the new version by checking Help > About Adobe Acrobat/Reader DC shows a version newer than 21.006.20060, 20.004.30012, or 17.011.30210
Caveat Standard upgrade risks apply - ensure compatibility testing with existing workflows and verify no custom plugins or integrations are affected

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

Fix this in Acrobat Dc Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

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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-2021-28642 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