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Acrobat DcApplication · Adobe

CVE-2021-39859

MEDIUM · 5.5 CVSS v3.1 Published 2023-09-06
Fix available
A fix is available. Upgrade to 17.011.30202 / 20.004.30015 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 Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by a Use After Free vulnerability that could lead to disclosure of sensitive memory. An attacker could leverage this vulnerability to bypass mitigations such as ASLR. 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

Adobe Acrobat Reader DC contains a Use After Free vulnerability where memory is accessed after it has been freed, potentially exposing sensitive memory contents. An attacker can exploit this by crafting a malicious PDF file that, when opened by a victim, triggers the UAF condition to leak memory and potentially bypass ASLR mitigations.

MitigationUpdate Adobe Acrobat Reader DC to the latest patched version beyond 2021.005.20060, 2020.004.30006, or 2017.011.30199. Avoid opening untrusted or unexpected 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:>= 15.007.20033, <= 21.005.20060>= 15.007.20033, <= 21.005.20058
Acrobat Reader DcApplication
Affected:>= 15.007.20033, <= 21.005.20060>= 15.007.20033, <= 21.005.20058
AcrobatApplication
Affected:>= 17.011.30180, < 17.011.30202>= 20.001.30005, < 20.004.30015
Acrobat ReaderApplication
Affected:>= 17.011.30180, < 17.011.30202>= 20.001.30005, < 20.004.30015

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. Check Adobe Acrobat Reader DC version
    Open Adobe Acrobat Reader DC, go to Help > About Adobe Acrobat Reader DC, or check the version in Add/Remove Programs (Windows) or Applications folder (Mac)
    Affected if Version is between 15.007.20033 and 21.005.20060 inclusive (continuous range) or between 15.007.20033 and 21.005.20058 inclusive (continuous range)
  2. Check Adobe Acrobat DC version
    Open Adobe Acrobat DC, go to Help > About Adobe Acrobat DC, or check the version in Add/Remove Programs (Windows)
    Affected if Version is between 15.007.20033 and 21.005.20060 inclusive or between 15.007.20033 and 21.005.20058 inclusive
  3. Check Adobe Acrobat (classic) version
    Open Adobe Acrobat (not DC), go to Help > About Adobe Acrobat, or check the version in Add/Remove Programs (Windows)
    Affected if Version is between 17.011.30180 and 17.011.30202 (excluding 17.011.30202) or between 20.001.30005 and 20.004.30015 (excluding 20.004.30015)
  4. Check Adobe Acrobat Reader (classic) version
    Open Adobe Acrobat Reader (not DC), go to Help > About Adobe Acrobat Reader, or check the version in Add/Remove Programs (Windows)
    Affected if Version is between 17.011.30180 and 17.011.30202 (excluding 17.011.30202) or between 20.001.30005 and 20.004.30015 (excluding 20.004.30015)

User is affected if any Adobe Acrobat or Adobe Acrobat Reader version falls within the listed affected ranges and the application is used to open PDF files from untrusted sources.

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 17.011.30202 / 20.004.30015 or later
Fixed in 17.011.3020220.004.30015
Interim mitigation

Update Adobe Acrobat Reader DC to the latest patched version beyond 2021.005.20060, 2020.004.30006, or 2017.011.30199. Avoid opening untrusted or unexpected PDF files from unknown sources.

Recommended fix High confidence

Adobe Acrobat/Acrobat Reader DC Continuous: 2021.006.20060 or later; Classic 17.x: 17.011.30202 or later; Classic 20.x: 20.004.30015 or later

  1. 1. Determine the currently installed Adobe Acrobat or Acrobat Reader version by opening the application and navigating to Help > About Adobe Acrobat Reader DC (or About Adobe Acrobat DC)
  2. 2. Identify which product track you are using: Continuous (e.g., 21.xxxx.xxxxxx) or Classic (e.g., 17.xxxx.xxxxxx)
  3. 3. For Continuous track users: Upgrade to version 2021.006.20060 or later
  4. 4. For Classic track 17.x users: Upgrade to version 17.011.30202 or later
  5. 5. For Classic track 20.x users: Upgrade to version 20.004.30015 or later
  6. 6. Download the appropriate update from the official Adobe website at helpx.adobe.com
  7. 7. Run the installer and follow the prompts to complete the upgrade
  8. 8. Restart the application after installation
Caveat Standard minor version upgrade with no expected breaking changes; default settings and existing documents remain compatible

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

Fix this in Acrobat Dc Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
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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-2021-39859 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