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Acrobat DcApplication · Adobe

CVE-2021-28635

HIGH · 7.8 CVSS v3.1 Published 2021-08-20
Fix available
A fix is available. Upgrade to after 21.005.20054 or later.
See remediation →
81/100
Remediation priority · High
High EPSS No privileges Patch available

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 2021.005.20054 (and earlier), 2020.004.30005 (and earlier) and 2017.011.30197 (and earlier) are affected by a use-after-free 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
How this class of weakness works · CWE-416

Memory is used after it has been freed, so its contents — now potentially attacker-controlled — drive the program's behaviour. With careful heap grooming this becomes code execution. The fix requires disciplined ownership of memory and often a targeted rework of the object lifecycle.

General guidance for the use after free class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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, <= 21.005.20054>= 17.011.30059, <= 17.011.30197>= 20.001.30005, <= 20.004.30005
Acrobat Reader DcApplication
Affected:>= 15.008.20082, <= 21.005.20054>= 17.011.30059, <= 17.011.30197>= 20.001.30005, <= 20.004.30005

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

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 21.005.20054
Vendor patch helpx.adobe.com →
Recommended fix High confidence

Upgrade to Adobe Acrobat/Reader DC 2021.005.20060 or later (2021 track), 2020.004.30012 or later (2020 track), or 2017.011.30201 or later (2017 track)

  1. 1. Verify current Adobe Acrobat/Reader version by opening the application, clicking 'Help' > 'About Adobe Acrobat/Reader'
  2. 2. Determine which version track you are on (2021, 2020, or 2017) based on the displayed version number
  3. 3. For Adobe Acrobat DC: Navigate to https://helpx.adobe.com/security/products/acrobat/apsb21-51.html to obtain the latest patched version
  4. 4. For Adobe Acrobat Reader DC: Download the patched version from the same advisory page
  5. 5. Download the appropriate installer for your version track (2021.x, 2020.x, or 2017.x)
  6. 6. Close all Adobe applications and any applications that integrate with Adobe services
  7. 7. Run the installer and follow the prompts to complete the update
  8. 8. After installation, verify the new version by checking 'Help' > 'About Adobe Acrobat/Reader' to confirm you are running a fixed version (2021.005.20060 or later for 2021 track, 2020.004.30012 or later for 2020 track, 2017.011.30201 or later for 2017 track)
Caveat Minimal risk - Adobe patches are generally backward compatible with PDF files; users should test critical workflows after upgrading

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

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $3,200. Get the upgrade done

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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-2021-28635 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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