CVE-2021-34851

Code execution via multiply referenced Annotation dictionary

Published Aug 4, 2021 · Updated Aug 4, 2024

Use-after-free in Annotation handling in Foxit PDF Reader 11.0.0.49893 allows remote attackers to execute code through a crafted PDF. A PDF that references the same Annotation dictionary from multiple page structures creates multiple objects for shared state, allowing operations after the underlying object is freed. The target must open the file or visit a malicious page; successful exploitation runs code in the current process and can also crash it.

CVSS severity7.8
High
EPSS probability4.00%
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 Annotation handling in Foxit PDF Reader 11.0.0.49893 allows remote attackers to execute code through a crafted PDF. A PDF that references the same Annotation dictionary from multiple page structures creates multiple objects for shared state, allowing operations after the underlying object is freed. The target must open the file or visit a malicious page; successful exploitation runs code in the current process and can also crash it.

The record

CVE
CVE-2021-34851
Published
Aug 4, 2021
Updated
Aug 4, 2024
Vendor
Foxit Software
Product
Foxit PDF Reader
Classifications
CWE-416, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 4, 2021CVE 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=11.0.0.49893

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Foxit Software · Foxit PDF Readerversion=11.0.0.49893

Published CVSS scores

7.8NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:P/A:P

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.

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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
T1203Exploitation for Client Execution

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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