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Acrobat DcApplication · Adobe

CVE-2021-28554

HIGH · 7.8 CVSS v3.1 Published 2021-08-24
Fix available
A fix is available. Upgrade to after 21.001.20155 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 versions 2021.001.20155 (and earlier), 2020.001.30025 (and earlier) and 2017.011.30196 (and earlier) are affected by an Out-of-bounds Read 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

Adobe Acrobat Reader DC contains an out-of-bounds read vulnerability that allows an unauthenticated attacker to achieve arbitrary code execution in the context of the current user. Exploitation requires a victim to open a malicious PDF file, making user interaction a necessary condition for successful exploitation.

MitigationUpdate Adobe Acrobat Reader DC to the latest patched version beyond 2021.001.20155, 2020.001.30025, or 2017.011.30196. Additionally, educate users to avoid opening untrusted or unexpected PDF files from unverified 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:>= 15.008.20082, <= 21.001.20155
Acrobat Reader DcApplication
Affected:>= 15.008.20082, <= 21.001.20155
AcrobatApplication
Affected:>= 17.011.30180, <= 17.011.30196>= 20.001.30005, <= 20.001.30025
Acrobat ReaderApplication
Affected:>= 17.011.30180, <= 17.011.30196>= 20.001.30005, <= 20.001.30025

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. Locate installed Adobe Acrobat or Reader version
    Open Adobe Acrobat/Reader, go to Help > About Adobe Acrobat Reader DC (or About Adobe Acrobat). The version number appears in the title bar or dialog. Alternatively, check Windows Registry at HKLM\SOFTWARE\Adobe\Acrobat\DC\Version or HKLM\SOFTWARE\Adobe\Acrobat\Reader\DC\Version, or macOS application bundle Info.plist.
    Affected if Version number cannot be determined or version falls within affected ranges.
  2. Compare version against affected ranges for DC (Continuous) track
    If using Adobe Acrobat/Reader DC (Continuous), check if version starts with 15.x through 21.x. Specifically, note the version string (for example, 21.001.20155) and compare against the affected range 15.008.20082 through 21.001.20155.
    Affected if Version is 15.008.20082 or higher AND 21.001.20155 or lower.
  3. Compare version against affected ranges for 2017 (Classic) track
    If using Adobe Acrobat/Reader 2017 (Classic), check version against 17.011.30180 through 17.011.30196. Look for version strings starting with 17.011.
    Affected if Version is 17.011.30180 or higher AND 17.011.30196 or lower.
  4. Compare version against affected ranges for 2020 (Classic) track
    If using Adobe Acrobat/Reader 2020 (Classic), check version against 20.001.30005 through 20.001.30025. Look for version strings starting with 20.001.
    Affected if Version is 20.001.30005 or higher AND 20.001.30025 or lower.
  5. Verify if user opens PDF files from untrusted sources
    Since exploitation requires a victim to open a malicious PDF file, review user behavior or organizational policy regarding opening PDF attachments or files from untrusted or unknown sources.
    Affected if Users routinely open PDF files from untrusted or unexpected sources without verification.

A user is affected if their installed Adobe Acrobat or Reader version falls within any of the specified vulnerable ranges (15.008.20082-21.001.20155 for DC, 17.011.30180-17.011.30196 for 2017 Classic, or 20.001.30005-20.001.30025 for 2020 Classic) AND they may 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 a release after 21.001.20155
Interim mitigation

Update Adobe Acrobat Reader DC to the latest patched version beyond 2021.001.20155, 2020.001.30025, or 2017.011.30196. Additionally, educate users to avoid opening untrusted or unexpected PDF files from unverified sources.

Recommended fix High confidence

Acrobat DC/Reader DC: 2021.001.20159 or later; 2020 track: 2020.001.30026 or later; 2017 track: 2017.011.30197 or later

  1. 1. Verify the currently installed Adobe Acrobat or Acrobat Reader version by opening the application, clicking 'Help' > 'About Adobe Acrobat Reader' (or 'About Adobe Acrobat' for the full product)
  2. 2. Identify which product and version track (2017, 2020, or 2021/DC) is installed from the affected version ranges listed
  3. 3. For Acrobat DC/Acrobat Reader DC users: upgrade to version 2021.001.20159 or later
  4. 4. For Acrobat/Acrobat Reader 2020 track users: upgrade to version 2020.001.30026 or later
  5. 5. For Acrobat/Acrobat Reader 2017 track users: upgrade to version 2017.011.30197 or later
  6. 6. Download the updated version from the official Adobe website or use the built-in update mechanism (Help > Check for Updates)
  7. 7. Restart the application after installation
  8. 8. Confirm the version has been updated by checking Help > About to verify the fix is applied
Caveat Standard upgrade risks apply - ensure compatibility with existing workflows and verify any required PDF plugins function correctly after updating

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
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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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-2021-28554 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