CVE-2021-44557

File disclosure and denial of service via XXE

Published Dec 8, 2021 · Updated Aug 4, 2024

XXE in National Library of the Netherlands multiNER allows attackers to read internal files or interrupt service via crafted XML. multiNER/ner.py parses attacker-controlled XML with external-entity resolution enabled, causing declared entities to access internal resources. Exploitation requires an application path that passes untrusted XML to the parser; the documented consequences are file disclosure and service interruption.

CVSS severityUnavailable
Unscored
EPSS probability1.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XXE in National Library of the Netherlands multiNER allows attackers to read internal files or interrupt service via crafted XML. multiNER/ner.py parses attacker-controlled XML with external-entity resolution enabled, causing declared entities to access internal resources. Exploitation requires an application path that passes untrusted XML to the parser; the documented consequences are file disclosure and service interruption.

The record

CVE
CVE-2021-44557
Published
Dec 8, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-611
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 8, 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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

No CVSS assessment is available in this record.

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-611Improper Restriction of XML External Entity Reference

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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