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Vulnerabilities

Vulnerability · CVE-2021-21017

Adobe Acrobat and Reader Heap-based Buffer Overflow Vulnerability

Published Feb 9, 2021 · catalog updated Jun 16, 2026 · Adobe Acrobat and Reader

Patch now

CVE-2021-21017 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Adobe Acrobat and Reader against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
High8.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
86.33%
Remediation
Remediation guidance
Affected products
cpe adobe/acrobat · cpe adobe/acrobat dc · cpe adobe/acrobat reader · cpe adobe/acrobat reader dc · vendor Adobe Acrobat and Reader

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe adobe/acrobatversion unspecified
  • cpe adobe/acrobat dcversion unspecified
  • cpe adobe/acrobat readerversion unspecified
  • cpe adobe/acrobat reader dcversion unspecified
  • vendor Adobe Acrobat and Readerversion unspecified

How to fix CVE-2021-21017

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-21017 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Adobe Acrobat and Reader against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply updates per vendor instructions.

What should an analyst verify?

CWE-122: Heap-based Buffer Overflow; CWE-787: Out-of-bounds Write. EPSS 86.33%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 11, 2021 · Catalog

    Detected

    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 ope

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Nov 17, 2021 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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 ope

Sources

  • CISA KEVConfirmed exploitationCVE-2021-21017

    Acrobat Acrobat and Reader contain a heap-based buffer overflow vulnerability that could allow an unauthenticated attacker to achieve code execution in the context of the current user.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-21017

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-21017

    30-day exploitation probability 86.3%

    first.org
  • NIST NVDVulnerability recordCVE-2021-21017

    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 exec

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2021-21017

    Acrobat Acrobat and Reader contain a heap-based buffer overflow vulnerability that could allow an unauthenticated attacker to achieve code execution in the context of the current user.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.