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NVD / CVE Program· CNA adobe

CVE-2021-21017: Acrobat Reader DC Heap-based Buffer Overflow Vulnerability Could Lead To Arbitrary Code Execution

HighCVSS 8.8 · v3.1KEVWeaponized No fix recorded

Noroxi assessment

Priority: Now (action score 91/100)

  • CISA has confirmed exploitation in the wild (Nov 3, 2021). Remediation deadline for US federal agencies: Nov 17, 2021.
  • Probability of exploitation in the next 30 days: 86.2% (FIRST EPSS); higher than 99.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Patch today or shut off access. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by a heap-based buffer overflow 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.

Published
Feb 11, 2021
Updated
Jun 16, 2026
EPSS
86.2% · 99th percentile

Report tools

JSON

Action score

91

Now

Patch today or shut off access.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
26 / 30 · 86.2%

CISA SSVC decision

Exploitation
active
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · adobe
8.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Nov 3, 2021. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Nov 17, 2021.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-21017

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
adobeacrobat
adobeacrobat dc
adobeacrobat reader
adobeacrobat reader dc
applemacos
microsoftwindows

Versions reported by the vendor

Affected version ranges reported by the assigning authority (adobe). Independent of NVD's CPE analysis and usually ahead of it.

  • Adobe Acrobat Reader

    • unspecified and later · up to and including 2020.013.20074affected
    • unspecified and later · up to and including 2020.001.30018affected
    • unspecified and later · up to and including 2017.011.30188affected
    • unspecified and later · up to and including Noneaffected
Affected versions · NVD (6)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • adobe acrobat17.0 and later · up to 17.011.30188 inclusive
  • adobe acrobat20.0 and later · up to 20.001.30018 inclusive
  • adobe acrobat dcup to 20.013.20074 inclusive
  • adobe acrobat reader17.0 and later · up to 17.011.30188 inclusive
  • adobe acrobat reader20.0 and later · up to 20.001.300183 inclusive
  • adobe acrobat reader dcup to 20.013.20074 inclusive

Same product

adobe: all records

Other highest-scoring records for the same primary product.

  • CVE-2011-2462Unspecified vulnerability in the U3D component in Adobe Reader and Acrobat 10.1.1 and earlier on Windows and Mac OS X, and Adobe Reader 9.x…KEV
    96Now
  • CVE-2013-3346Adobe Reader and Acrobat 9.x before 9.5.5, 10.x before 10.1.7, and 11.x before 11.0.03 allow attackers to execute arbitrary code or cause a…KEV
    93Now
  • CVE-2009-3459Heap-based buffer overflow in Adobe Reader and Acrobat 7.x before 7.1.4, 8.x before 8.1.7, and 9.x before 9.2 allows remote attackers to…KEV
    91Now

Published before and after this one in the same product

  • ← EarlierCVE-2020-24438Nov 5, 2020 · Acrobat Reader DC Use-After-Free Vulnerability Could Lead to Information Disclosure
    14Monitor
  • ← EarlierCVE-2020-24439Nov 5, 2020 · Acrobat Reader DC for macOS Signature Validation Bypass
    11Monitor
  • Later →CVE-2021-21021Feb 11, 2021 · Acrobat Reader DC Use-After-Free Vulnerability Could Lead To Arbitrary Code Execution
    36Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHub3 repositories2021-02-26 → 2026-11-12

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+14 d
  3. CISA KEV+264 d
  4. TodayNov 14, 2026+2101 d

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-122 · Heap-based Buffer Overflow

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records