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Acrobat DcApplication · Adobe

CVE-2021-40728

HIGH · 7.8 CVSS v3.1 Published 2021-10-15
Fix available
A fix is available. Upgrade to after 21.007.20096 or later.
See remediation →
81/100
Remediation priority · High
High EPSS 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
Adobe Acrobat Reader DC version 21.007.20095 (and earlier), 21.007.20096 (and earlier), 20.004.30015 (and earlier), and 17.011.30202 (and earlier) is affected by a use-after-free vulnerability in the processing of the GetURL function on a global object window that could result in 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

A use-after-free vulnerability exists in Adobe Acrobat Reader DC's JavaScript engine when processing the GetURL function on the global window object. The vulnerability occurs because memory is freed but pointers are not nullified, allowing attackers to manipulate freed memory and achieve arbitrary code execution through malicious PDF files.

MitigationUpdate Adobe Acrobat Reader DC to the latest patched version; avoid opening untrusted or unsolicited PDF files until the update is applied.

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, <= 21.007.20095>= 15.008.20082, <= 21.007.20096
Acrobat Reader DcApplication
Affected:>= 15.008.20082, <= 21.007.20095>= 15.008.20082, <= 21.007.20096
AcrobatApplication
Affected:>= 20.001.30005, <= 20.004.30015>= 17.011.30158, <= 17.011.30202
Acrobat ReaderApplication
Affected:>= 20.001.30005, <= 20.004.30015>= 17.011.30158, <= 17.011.30202

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 Adobe Acrobat or Reader installation
    Open the application, go to Help > About Adobe Acrobat/Reader DC to view the exact version number. Alternatively, check Programs and Features (Windows) or the Applications folder (macOS).
    Affected if The installed version falls within 15.008.20082 to 21.007.20095/20096 (DC versions) or 20.001.30005 to 20.004.30015 / 17.011.30158 to 17.011.30202 (classic versions).
  2. Check if JavaScript is enabled in PDF settings
    Go to Edit > Preferences > JavaScript (Windows) or Acrobat/Reader > Preferences > JavaScript (macOS). Verify if 'Enable Adobe JavaScript' is checked.
    Affected if JavaScript is enabled; the vulnerability requires JavaScript processing to be active to trigger the use-after-free.
  3. Confirm the product type and build
    Look at the exact build number shown in the About dialog. DC versions have 'DC' in the name, classic versions have numeric year releases (e.g., 2020, 2017).
    Affected if The build number matches any of the affected version ranges provided in the CVE.

The environment is affected if Adobe Acrobat or Reader is installed with a version matching the affected ranges AND JavaScript is enabled in the PDF settings, allowing malicious PDFs to trigger the use-after-free via the GetURL function.

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 21.007.20096
Interim mitigation

Update Adobe Acrobat Reader DC to the latest patched version; avoid opening untrusted or unsolicited PDF files until the update is applied.

Recommended fix High confidence

Adobe Acrobat Reader DC / Acrobat DC version 21.007.20097 or later, 20.004.30016 or later, 17.011.30203 or later (depending on your release track)

  1. 1. Open Adobe Acrobat Reader DC or Adobe Acrobat DC application
  2. 2. Navigate to Help > Check for Updates (or Help > About Adobe Acrobat Reader DC)
  3. 3. Allow the application to check for available updates
  4. 4. If updates are available, download and install the latest security update
  5. 5. Alternatively, manually download the latest version from the official Adobe website: https://get.adobe.com/reader/ (for Reader) or https://get.adobe.com/acrobat/ (for Acrobat)
  6. 6. After installation, verify the version by going to Help > About to confirm the version number reflects a fixed release
Caveat Adobe updates typically include additional feature changes; review release notes before deploying in production environments

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
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2021-40728 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