CVE-2021-39371Network attack vector

Unauthenticated file disclosure via external entity resolution

Published Aug 23, 2021 · Updated Aug 4, 2024

XML external entity injection in OSGeo PyWPS before 4.4.5 allows remote attackers to read server files via crafted WPS XML requests. WPSRequest._post_request passes request bodies to lxml.etree.fromstring with the default parser, which resolves attacker-supplied external entities. No authentication or user interaction is required, and the bounded impact is disclosure of files readable by the service account.

CVSS severity8.7
High
EPSS probability1.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XML external entity injection in OSGeo PyWPS before 4.4.5 allows remote attackers to read server files via crafted WPS XML requests. WPSRequest._post_request passes request bodies to lxml.etree.fromstring with the default parser, which resolves attacker-supplied external entities. No authentication or user interaction is required, and the bounded impact is disclosure of files readable by the service account.

The record

CVE
CVE-2021-39371
Published
Aug 23, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-611, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 23, 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:H/I:N/A:N
8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

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
T1005Data from Local System

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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