CVE-2021-20453Network attack vector

Information disclosure and memory exhaustion via XXE

Published Apr 20, 2021 · Updated Sep 17, 2024

XXE injection in IBM WebSphere Application Server 8.0, 8.5, and 9.0 allows remote attackers to disclose data or exhaust memory. IBM has not identified the XML-processing component or disclosed how it permits external entity resolution on untrusted XML. No authentication or user interaction is required; successful exploitation reads sensitive information or interrupts service through memory exhaustion.

CVSS severity8.2
High
EPSS probability2.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XXE injection in IBM WebSphere Application Server 8.0, 8.5, and 9.0 allows remote attackers to disclose data or exhaust memory. IBM has not identified the XML-processing component or disclosed how it permits external entity resolution on untrusted XML. No authentication or user interaction is required; successful exploitation reads sensitive information or interrupts service through memory exhaustion.

The record

CVE
CVE-2021-20453
Published
Apr 20, 2021
Updated
Sep 17, 2024
Vendor
IBM
Product
IBM WebSphere Application Server
Classifications
CWE-611, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=8.0
  2. Affected versionversion=8.5
  3. Affected versionversion=9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · IBM WebSphere Application Serverversion=8.0; version=8.5; version=9.0

Published CVSS scores

8.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
8.2IBM CorporationCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
6.4NIST NVDAV:N/AC:L/Au:N/C:P/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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-611Improper Restriction of XML External Entity Reference
T1190Exploit Public-Facing Application

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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