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AcrobatApplication · Adobe

CVE-2021-39860

MEDIUM · 5.5 CVSS v3.1 Published 2021-09-29
Fix available
A fix is available. Upgrade to after 21.005.20060 or later.
See remediation →
58/100
Remediation priority · Elevated
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 Pro DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by a Null pointer dereference vulnerability. An unauthenticated attacker could leverage this vulnerability to disclose sensitive user memory. 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 · moderate confidence

A null pointer dereference vulnerability in Adobe Acrobat Pro DC allows an unauthenticated attacker to disclose sensitive user memory by tricking a victim into opening a malicious PDF file. This client-side vulnerability affects multiple older version ranges across three major product versions.

MitigationUpdate Adobe Acrobat Pro DC to the latest patched version beyond 2021.005.20060, 2020.004.30006, or 2017.011.30199 as applicable. Additionally, train 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:>= 17.011.30059, <= 17.011.30199>= 20.001.30005, <= 20.004.30006
Acrobat ReaderApplication
Affected:>= 17.011.30059, <= 17.011.30199>= 20.001.30005, <= 20.004.30006
Acrobat DcApplication
Affected:>= 15.008.20082, <= 21.005.20058>= 15.008.20082, <= 21.005.20060
Acrobat Reader DcApplication
Affected:>= 15.008.20082, <= 21.005.20058>= 15.008.20082, <= 21.005.20060

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
None
Availability
None

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

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 the installed Adobe product
    On Windows, open the application and go to Help > About Adobe Acrobat/Reader, or check Add/Remove Programs. On Mac, check the application name in Applications folder (e.g., Adobe Acrobat DC, Adobe Acrobat Reader DC).
    Affected if The product is Adobe Acrobat Pro DC, Adobe Acrobat, Adobe Acrobat Reader, or their DC variants.
  2. Determine the exact version number
    In the About dialog, record the full version number displayed (for example, 21.005.20093). On Windows, you can also check the registry key under HKLM\SOFTWARE\Adobe\Adobe Acrobat\DC\Version or HKLM\SOFTWARE\Adobe\Acrobat Reader\DC\Version.
    Affected if A version number is displayed that can be compared against the affected ranges.
  3. Check if version falls within the first affected range
    Compare your installed version to 15.008.20082 through 21.005.20058 (for DC/Reader DC products). If your version is between 15.008.20082 and 21.005.20058 inclusive, you are in the affected range.
    Affected if The installed version is >= 15.008.20082 and <= 21.005.20058 (for DC variants).
  4. Check if version falls within the second DC range
    For DC/Reader DC products, also compare to 15.008.20082 through 21.005.20060. If your version is between 15.008.20082 and 21.005.20060 inclusive, you are affected.
    Affected if The installed version is >= 15.008.20082 and <= 21.005.20060 (for DC variants).
  5. Check Classic version ranges for non-DC products
    For non-DC Acrobat/Reader, compare your version to: 17.011.30059 through 17.011.30199, OR 20.001.30005 through 20.004.30006. If it falls in either range, you are affected.
    Affected if The installed version is >= 17.011.30059 and <= 17.011.30199, OR >= 20.001.30005 and <= 20.004.30006.

A user is affected if they have any Adobe Acrobat or Reader product installed with a version matching the affected ranges, specifically versions 15.x through 21.x for DC variants or 17.x/20.x for Classic variants, within the specified boundaries.

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 21.005.20060
Interim mitigation

Update Adobe Acrobat Pro DC to the latest patched version beyond 2021.005.20060, 2020.004.30006, or 2017.011.30199 as applicable. Additionally, train users to avoid opening untrusted PDF files.

Recommended fix High confidence

Upgrade to Adobe Acrobat DC 2021.006 or later; Acrobat Reader DC 2021.006 or later; Acrobat 2017.011.30198 or earlier should upgrade to latest 2017 release; Acrobat 2020.004.30006 or earlier should upgrade to latest 2020 release

  1. 1. Close all Adobe Acrobat or Acrobat Reader instances currently running on the system
  2. 2. Navigate to the Adobe Acrobat download page at https://get.adobe.com/reader/ (for Reader) or https://get.adobe.com/acrobat/ (for Pro)
  3. 3. Download the latest version of Adobe Acrobat Reader DC or Adobe Acrobat Pro DC
  4. 4. Run the installer and follow the prompts to complete the installation
  5. 5. Alternatively, use Adobe's official patching mechanism via Help > Check for Updates within the application
  6. 6. Verify the installation was successful by opening Adobe Acrobat/Reader and checking the version under Help > About Adobe Acrobat Reader/Acrobat
Caveat Standard upgrade - ensure compatibility with existing PDF workflows and plugins; enterprise deployments should test in staging environment first

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

Fix this in Acrobat Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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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-2021-39860 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