CVE-2021-44704
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 · uneditedAcrobat Reader DC version 21.007.20099 (and earlier), 20.004.30017 (and earlier) and 17.011.30204 (and earlier) are affected by a use-after-free vulnerability in the processing of Format event actions 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 confidenceA use-after-free vulnerability exists in Adobe Acrobat Reader DC when processing Format event actions in PDF files. The vulnerability occurs when memory is freed but pointers to that memory are not properly invalidated, allowing the freed memory to be accessed and potentially exploited for arbitrary code execution in the context of the current user.
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>= 15.008.20082, <= 21.007.20099>= 15.008.20082, <= 21.007.20099>= 17.011.30059, <= 17.011.30204>= 20.001.30005, <= 20.004.30017>= 17.011.30059, <= 17.011.30204>= 20.001.30005, <= 20.004.30017CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Confirm Adobe Acrobat or Reader is installedOpen Windows Control Panel and go to Programs and Features, or check the Windows Registry at HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall for entries starting with 'Adobe Acrobat' or 'Adobe Reader'Affected if The application is not installed, then you are not affected by this vulnerability
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Determine the exact product versionIf the application is installed, open it and go to Help > About Adobe Acrobat (or Reader) to display the exact version number, or check the DisplayVersion value in the Registry under the product's uninstall entryAffected if The version cannot be determined, treat as potentially affected
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Check if version falls within the first vulnerable DC range (2021)Compare your version number to the range 15.008.20082 through 21.007.20099 for Adobe Acrobat DC or Adobe Acrobat Reader DC products. Note the version format uses a year.month format (21.xxx)Affected if Your installed version is >= 15.008.20082 AND <= 21.007.20099, then you are affected
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Check if version falls within the second vulnerable DC range (Continuous)If you have version 17.011.x, verify it is between 17.011.30059 and 17.011.30204 inclusive. If you have version 20.xxx, verify it is between 20.001.30005 and 20.004.30017 inclusiveAffected if Your version is between 17.011.30059 and 17.011.30204, OR between 20.001.30005 and 20.004.30017, then you are affected
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Verify the Format event action trigger conditionThis vulnerability exploits Format event actions in PDF files. A user must open a specially crafted PDF file containing malicious Format event actions for the vulnerability to be triggered. Check if your PDF viewing habits involve opening files from untrusted sourcesAffected if You regularly open PDF files from unknown or untrusted sources, your exposure risk is higher
You are affected if Adobe Acrobat or Adobe Acrobat Reader is installed AND the version falls within any of the following ranges: 15.008.20082 to 21.007.20099, 17.011.30059 to 17.011.30204, or 20.001.30005 to 20.004.30017.
Generated from the published advisory. Verify against your own configuration.
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 · scopedApply vendor-supplied patches: update to Acrobat Reader DC 21.007.20099+ (Continuous), 20.004.30017+ (Classic 2020), or 17.011.30204+ (Classic 2017). Additionally, educate users to avoid opening untrusted PDF files.
Adobe Acrobat DC/Reader DC version 21.008.20092 or later; version 20.005.30006 or later; version 18.x or later
- 1. Verify the current 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. Download the latest version of Adobe Acrobat DC or Acrobat Reader DC from the official Adobe website at https://get.adobe.com/reader/ (for Reader) or https://get.adobe.com/acrobat/ (for Acrobat)
- 3. Close all running instances of Adobe Acrobat or Acrobat Reader
- 4. Run the installer for the latest version and follow the on-screen prompts to complete the upgrade
- 5. After installation, verify the version has been updated to a version newer than the vulnerable releases (21.008.x, 20.005.x, or 18.x and later)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-44704 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-44704 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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