CVE-2021-38566Network attack vector

Application crash via unbounded XML recursion

Published Aug 11, 2021 · Updated Aug 4, 2024

Uncontrolled recursion in Foxit PDF Reader and PDF Editor before 11.0.1 allows attackers to crash the application via crafted embedded XML. The XML parser recursively processes nested nodes without enforcing a safe depth limit, consuming the call stack until the process fails. The flaw is reached when an affected application parses a PDF containing excessively nested XML, and the documented consequence is an application crash only.

CVSS severity7.5
High
EPSS probability0.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in Foxit PDF Reader and PDF Editor before 11.0.1 allows attackers to crash the application via crafted embedded XML. The XML parser recursively processes nested nodes without enforcing a safe depth limit, consuming the call stack until the process fails. The flaw is reached when an affected application parses a PDF containing excessively nested XML, and the documented consequence is an application crash only.

The record

CVE
CVE-2021-38566
Published
Aug 11, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-674, CAPEC-231, CAPEC-230, T1499.004
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

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-674Uncontrolled Recursion
CAPEC-231Oversized Serialized Data Payloads
CAPEC-230Serialized Data with Nested Payloads
T1499.004Application or System Exploitation

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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