CVE-2021-38563Network attack vector

Application crash via undersized indirect-object offset array

Published Aug 11, 2021 · Updated Aug 4, 2024

Out-of-bounds access in Foxit PDF Reader and PDF Editor before 11.0.1 allows context-dependent attackers to crash the application. The PDF parser sizes an indirect-object offset array from the trailer's /Size value, then indexes it with a larger object number without validating that the array can hold the entry. A crafted PDF must reach the parser; the documented consequences are a NULL pointer dereference or out-of-bounds read or write, with an application crash explicitly confirmed.

CVSS severity9.8
Critical
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Foxit PDF Reader and PDF Editor before 11.0.1 allows context-dependent attackers to crash the application. The PDF parser sizes an indirect-object offset array from the trailer's /Size value, then indexes it with a larger object number without validating that the array can hold the entry. A crafted PDF must reach the parser; the documented consequences are a NULL pointer dereference or out-of-bounds read or write, with an application crash explicitly confirmed.

The record

CVE
CVE-2021-38563
Published
Aug 11, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-129
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-129Improper Validation of Array Index

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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