CVE-2021-41098Network attack vector

Data disclosure via default external entity resolution

Published Sep 27, 2021 · Updated Aug 4, 2024

XXE in Nokogiri 1.12.4 and earlier on JRuby allows remote attackers to disclose data through crafted SAX documents. The JRuby SAX parser constructs Xerces parsers without NokogiriEntityResolver, so external identifiers resolve under permissive defaults. Exposure requires an application to pass attacker-controlled XML or HTML to an affected SAX or PushParser class; CRuby is unaffected.

CVSS severity7.5
High
EPSS probability1.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XXE in Nokogiri 1.12.4 and earlier on JRuby allows remote attackers to disclose data through crafted SAX documents. The JRuby SAX parser constructs Xerces parsers without NokogiriEntityResolver, so external identifiers resolve under permissive defaults. Exposure requires an application to pass attacker-controlled XML or HTML to an affected SAX or PushParser class; CRuby is unaffected.

The record

CVE
CVE-2021-41098
Published
Sep 27, 2021
Updated
Aug 4, 2024
Vendor
Sparkle Motion
Product
Nokogiri
Classifications
CWE-611, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 27, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.12.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sparkle Motion · Nokogiriversion=< 1.12.5

Published CVSS scores

7.5Nokogiri maintainers via GitHubCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A: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.

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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)
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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