CVE-2021-27906

Service crash via crafted PDF loading

Published Mar 19, 2021 · Updated Feb 13, 2025

Apache PDFBox 2.0.22 and earlier allows attackers to trigger service interruption by loading a carefully crafted PDF file. PDFXrefStreamParser builds unchecked cross-reference structures and allocates excessive memory before parsing completes, so attacker-controlled values can cause an OutOfMemory exception. The gate is access to an application or utility that processes the PDF; the consequence is process exhaustion or termination without reported confidentiality or integrity impact.

CVSS severity5.5
Medium
EPSS probability3.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Apache PDFBox 2.0.22 and earlier allows attackers to trigger service interruption by loading a carefully crafted PDF file. PDFXrefStreamParser builds unchecked cross-reference structures and allocates excessive memory before parsing completes, so attacker-controlled values can cause an OutOfMemory exception. The gate is access to an application or utility that processes the PDF; the consequence is process exhaustion or termination without reported confidentiality or integrity impact.

The record

CVE
CVE-2021-27906
Published
Mar 19, 2021
Updated
Feb 13, 2025
Vendor
The Apache Software Foundation
Product
Apache PDFBox
Classifications
CWE-789, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record 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=Apache PDFBox <=2.0.22

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache PDFBoxversion=Apache PDFBox <=2.0.22

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
T1499.004Endpoint Denial of Service: Resource Exhaustion

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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