CVE-2021-21058

Current-user code execution via PDF buffer overflow

Published Feb 11, 2021 · Updated Sep 16, 2024

Buffer overflow in Adobe Acrobat Reader allows context-dependent attackers to execute code when a user opens a crafted PDF file. Its PDF parser writes beyond a memory buffer while parsing malformed document data; Adobe has not disclosed a narrower structure or code locus. Opening the malicious PDF is required, and successful exploitation runs arbitrary code with the current user's privileges on Windows or macOS.

CVSS severity7.8
High
EPSS probability2.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Adobe Acrobat Reader allows context-dependent attackers to execute code when a user opens a crafted PDF file. Its PDF parser writes beyond a memory buffer while parsing malformed document data; Adobe has not disclosed a narrower structure or code locus. Opening the malicious PDF is required, and successful exploitation runs arbitrary code with the current user's privileges on Windows or macOS.

The record

CVE
CVE-2021-21058
Published
Feb 11, 2021
Updated
Sep 16, 2024
Vendor
Adobe
Product
Adobe Acrobat Reader
Classifications
CWE-787, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=2017.011.30188
  2. Affected versionversion=unspecified <=2020.001.30018
  3. Affected versionversion=unspecified <=2020.013.20074
  4. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Acrobat Readerversion=unspecified <=2017.011.30188; version=unspecified <=2020.001.30018; version=unspecified <=2020.013.20074; version=unspecified <=None

Published CVSS scores

7.8Adobe Systems IncorporatedCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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