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AcrobatApplication · Adobe

CVE-2021-39846

MEDIUM · 6.1 CVSS v3.1 Published 2021-09-29
Fix available
A fix is available. Upgrade to after 21.005.20060 or later.
See remediation →
64/100
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 Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by a stack overflow vulnerability due to insecure handling of a crafted PDF file, potentially resulting in memory corruption in the context of the current user. Exploitation requires user interaction in that a victim must open a crafted PDF file in Acrobat Reader.

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 stack overflow vulnerability when processing specially crafted PDF files, leading to potential memory corruption in the current user's context. Exploitation requires the victim to open a malicious PDF file, making it a client-side vulnerability requiring user interaction.

MitigationUpdate Adobe Acrobat Reader DC to a version newer than 2021.005.20060, 2020.004.30006, or 2017.011.30199 respectively, or apply the latest security patch from Adobe.

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:>= 20.001.30005, <= 20.004.30006>= 17.011.30059, <= 17.011.30199
Acrobat ReaderApplication
Affected:>= 20.001.30005, <= 20.004.30006>= 17.011.30059, <= 17.011.30199
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
None
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/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 the installed Adobe product
    Open Adobe Acrobat or Reader, then go to Help > About Adobe Acrobat Reader (or About Adobe Acrobat). Alternatively, check the installed program version in Windows Control Panel > Programs and Features, or on macOS in Applications folder Get Info.
    Affected if The product name matches Adobe Acrobat, Adobe Acrobat Reader, Adobe Acrobat DC, or Adobe Acrobat Reader DC
  2. Determine the exact version number
    Note the full version string displayed in the About dialog (for example: 21.005.20058 or 20.004.30006). In Windows, you can also right-click the executable in Program Files and view Properties > Details for the File Version.
    Affected if The version falls within any of these ranges: 20.001.30005 to 20.004.30006, 17.011.30059 to 17.011.30199, 15.008.20082 to 21.005.20058, or 15.008.20082 to 21.005.20060 (depending on product type)
  3. Verify the application can open PDF files
    Confirm that the PDF file handling functionality is enabled and the application can process PDF documents. This is the default state for standard installations.
    Affected if PDF functionality is enabled and the application can open PDF files (this is the default configuration)

The user is affected if they have Adobe Acrobat, Acrobat Reader, Acrobat DC, or Reader DC installed with a version matching any of the vulnerable ranges and the application can open PDF files, which is the default configuration.

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 Reader DC to a version newer than 2021.005.20060, 2020.004.30006, or 2017.011.30199 respectively, or apply the latest security patch from Adobe.

Recommended fix High confidence

Upgrade to Adobe Acrobat/Reader DC 2021.006.x or later, 2020.005.x or later, or 2017.012.x or later - specific patch releases were provided via Adobe security bulletin APSB21-55

  1. 1. Verify current Adobe Acrobat or Acrobat Reader version by opening the application, selecting 'Help' > 'About Adobe Acrobat/Reader'
  2. 2. Close all Adobe applications completely before updating
  3. 3. Open Adobe Acrobat Reader DC or Acrobat DC
  4. 4. Navigate to 'Help' > 'Check for Updates' to automatically download and install the latest version
  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. Run the installer and follow the on-screen prompts to complete the upgrade
  7. 7. After installation, verify the new version by checking 'Help' > 'About' to confirm you are on a fixed release (2021.006.x, 2020.005.x, or 2017.012.x or later)
Caveat Adobe updates typically include security fixes and may include feature changes; review release notes for any behavior changes before deploying enterprise-wide

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

Fix this in Acrobat Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing0.5 h
  • Review / QA0.5 h
3.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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-2021-39846 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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