CVE-2021-34957

Code execution via unchecked Highlight Annotation object

Published May 7, 2024 · Updated Aug 4, 2024

Use-after-free in Foxit PDF Reader and PDF Editor for Windows allows remote attackers to execute code via a crafted PDF. Highlight Annotation handling performs operations on an object without verifying that it still exists, allowing freed memory to be reused. Remote attackers must persuade a user to open the malicious file or visit a malicious page; successful exploitation runs code in the current process and can crash the application.

CVSS severity7.8
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Foxit PDF Reader and PDF Editor for Windows allows remote attackers to execute code via a crafted PDF. Highlight Annotation handling performs operations on an object without verifying that it still exists, allowing freed memory to be reused. Remote attackers must persuade a user to open the malicious file or visit a malicious page; successful exploitation runs code in the current process and can crash the application.

The record

CVE
CVE-2021-34957
Published
May 7, 2024
Updated
Aug 4, 2024
Vendor
Foxit Software
Product
Foxit PDF Reader
Classifications
CWE-416, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 7, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=0 <=11.0.1.49983

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Foxit Software · Foxit PDF Readerversion=0 <=11.0.1.49983
Foxit Software · Foxit PDF Editorversion=0 <=10.1.5.37672; version=0 <=11.0.0.49983; version=0 <=11.0.1.4938; version=11.0.0.49893

Published CVSS scores

7.8Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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-416Use After Free
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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