Acrobat DcApplication · Adobe

CVE-2021-28550

HIGH · 8.8 CVSS v3.1 Published 2021-09-02

Fix available

A fix is available. Upgrade to after 21.001.20150 or later.

See remediation →

100/100

Remediation priority · Urgent

In the wild High EPSS Remotely reachable No privileges

Official description

NVD · unedited

Acrobat Reader DC versions versions 2021.001.20150 (and earlier), 2020.001.30020 (and earlier) and 2017.011.30194 (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

dbcve analysis · moderate confidence

Use After Free vulnerability in Adobe Acrobat Reader DC allows arbitrary code execution when a victim opens a maliciously crafted PDF file. The attacker does not need authentication, but relies on user interaction to trigger the flaw.

MitigationUpdate Adobe Acrobat Reader DC to the latest version (2021.001.20150+ for 2021 track, 2020.001.30020+ for 2020 track, 2017.011.30194+ for 2017 track). Until patched, avoid opening untrusted PDF files.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

NVD · CPE data

Acrobat DcApplication

Affected:>= 15.008.20082, <= 21.001.20150>= 15.008.20082, <= 21.001.20149

Acrobat Reader DcApplication

Affected:>= 15.008.20082, <= 21.001.20150>= 15.008.20082, <= 21.001.20149

AcrobatApplication

Affected:>= 17.011.30059, <= 17.011.30194>= 20.001.30005, <= 20.001.30020

Acrobat ReaderApplication

Affected:>= 17.011.30059, <= 17.011.30194>= 20.001.30005, <= 20.001.30020

CVSS breakdown

From the vector

Attack vector: Network
Complexity: Low
Privileges: None
User interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected?

dbcve checks

Work through these to decide whether this CVE applies to you.

Confirm Adobe Acrobat or Reader installation

Check if Adobe Acrobat DC, Adobe Acrobat Reader DC, Adobe Acrobat, or Adobe Acrobat Reader is installed on the system. On Windows, look in Program Files for Adobe folders, or check Add/Remove Programs. On macOS, check /Applications for Adobe Acrobat apps.

Affected if Any of these products are installed, proceed to version check.
Determine the installed version number

Open the application, then go to Help > About Adobe Acrobat Reader (or About Adobe Acrobat). Alternatively, on Windows, check the registry key HKLM\SOFTWARE\Adobe\Acrobat\Install\ or look at the version property of the executable file. On macOS, right-click the app and select Get Info to see the version.

Affected if A version number is found, proceed to compare against affected ranges.
Compare version against affected ranges

Match the installed version against the affected version ranges: Acrobat/Reader DC versions 15.008.20082 through 21.001.20150 (or 21.001.20149), Acrobat/Reader versions 17.011.30059 through 17.011.30194, and versions 20.001.30005 through 20.001.30020. Note that the version format may appear as 2021.xxxxxx, 2020.xxxxxx, 2017.xxxxxx, or similar.

Affected if The installed version falls within any of these ranges: 15.008.20082 to 21.001.20150, 17.011.30059 to 17.011.30194, or 20.001.30005 to 20.001.30020.
Identify the product branch

Determine whether the installation is Acrobat/Reader DC (continuous track with years in version, e.g., 2021, 2020) or classic Acrobat/Reader (with three-digit year, e.g., 17.x, 20.x). This helps narrow down which version range applies.

Affected if The product is in the DC track (versions like 21.001.xxxxxx or 20.001.xxxxxx) or classic track (versions like 17.011.xxxxxx or 20.001.xxxxxx).

The environment is affected if Adobe Acrobat or Reader is installed and its version falls within 15.008.20082-21.001.20150, 17.011.30059-17.011.30194, or 20.001.30005-20.001.30020.

Generated from the published advisory. Verify against your own configuration.

Remediation

dbcve · scoped

Upgrade available Upgrade to a release after 21.001.20150

Interim mitigation

Update Adobe Acrobat Reader DC to the latest version (2021.001.20150+ for 2021 track, 2020.001.30020+ for 2020 track, 2017.011.30194+ for 2017 track). Until patched, avoid opening untrusted PDF files.

Recommended fix High confidence

Acrobat Reader DC 2021.006.20060 (continuous) / 2021.001.20139 (classic) or later; Acrobat DC 2021.006.20060 (continuous) / 2021.001.20139 (classic) or later; Legacy: Acrobat 2017 to 2017.011.30195+, Acrobat 2020 to 2020.001.30025+

1. Verify 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. For Acrobat Reader DC continuous track: Upgrade to version 2021.006.20060 or later
3. For Acrobat Reader DC classic track: Upgrade to version 2021.001.20139 or later
4. For Acrobat DC continuous track: Upgrade to version 2021.006.20060 or later
5. For Acrobat DC classic track: Upgrade to version 2021.001.20139 or later
6. For legacy Acrobat 2017: Upgrade to version 2017.011.30195 or later
7. For legacy Acrobat 2020: Upgrade to version 2020.001.30025 or later
8. Download updates from official Adobe website at get.adobe.com/reader or helpx.adobe.com/acrobat/release-note.html

Caveat Standard Adobe update; minimal risk - verify compatibility with any third-party PDF plugins before deploying broadly

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

Fix this in Acrobat Dc Exploited in the wild — priority engagement

Consultation2.0 h
Implementation2.0 h
Testing2.0 h
Review / QA1.0 h

7.0 hours of engineering $1,240

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Scan for this in your stack

Free · runs locally

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References

Primary sources

helpx.adobe.comRelease NotesVendor Advisory
www.cisa.govThird Party AdvisoryUS Government Resource
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-28550 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2021-28550?

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

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

At a glance

Exploited in the wildOn CISA’s known-exploited list · agencies must fix by 2021-11-17

A fix existsUpgrade to after 21.001.20150 or later

Severity 8.8 High

Exploit likelihood EPSS, next 30 days 52.0%

Affects: Acrobat Dc

Remediation

Being exploited — close it fast

Fix this in Acrobat Dc 7 hrs · Moderate

Typical engagement from $1,240

Get it fixed fast See the full breakdown ↓

This CVE is on CISA’s actively-exploited list, so the clock is real — a vetted specialist can deliver a reviewed fix for your staging environment quickly.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References