CVE-2021-21250Network attack vector

Authenticated file disclosure via external entity expansion

Published Jan 15, 2021 · Updated Aug 3, 2024

XML external entity injection in OneDev before 4.0.3 allows remote authenticated users to read server files through crafted XML BuildSpec input. XmlBuildSpecMigrator.migrate parses attacker-controlled XML with a default SAXReader that accepts DTD declarations and expands external entities into the migrated document. Access to submit a BuildSpec is required; file contents can appear in generated YAML properties or leave the server through an out-of-band entity request.

CVSS severity7.7
High
EPSS probability0.93%
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 OneDev before 4.0.3 allows remote authenticated users to read server files through crafted XML BuildSpec input. XmlBuildSpecMigrator.migrate parses attacker-controlled XML with a default SAXReader that accepts DTD declarations and expands external entities into the migrated document. Access to submit a BuildSpec is required; file contents can appear in generated YAML properties or leave the server through an out-of-band entity request.

The record

CVE
CVE-2021-21250
Published
Jan 15, 2021
Updated
Aug 3, 2024
Vendor
OneDev Pty
Product
OneDev
Classifications
CWE-538, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=< 4.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OneDev Pty · OneDevversion=< 4.0.3

Published CVSS scores

7.7GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0NVDAV:N/AC:L/Au:S/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-538Insertion of Sensitive Information into Externally-Accessible File or Directory
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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