Improper Restriction of XML External Entity Reference (XXE) in Nokogiri on JRuby

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2021-41098: 1.46% estimated exploitation activity in the next 30 days; percentile 73.59 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Severity The Nokogiri maintainers have evaluated this as High Severity 7.5 (CVSS3.0) for JRuby users. (This security advisory does not apply to CRuby users.) Impact In Nokogiri v1.12.4 and earlier, on JRuby only, the SAX parser resolves external entities by default. Users of Nokogiri on JRuby who parse untrusted documents using any of these classes are affected: - Nokogiri::XML::SAX::Parser - Nokogiri::HTML4::SAX::Parser or its alias Nokogiri::HTML::SAX::Parser - Nokogiri::XML::SAX::PushParser - Nokogiri::HTML4::SAX::PushParser or its alias Nokogiri::HTML::SAX::PushParser Mitigation JRuby users should upgrade to Nokogiri v1.12.5 or later. There are no workarounds available for v1.12.4 or earlier. CRuby users are not affected.

Published by the source

27 Sep 2021, 20:12 UTC

Last modified by the source

4 May 2023, 19:54 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2rr5-8q37-2w7h

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# Patch Next advisory brief: CVE-2021-41098

Advisory: Improper Restriction of XML External Entity Reference (XXE) in Nokogiri on JRuby
IDs: CVE-2021-41098, GHSA-2rr5-8q37-2w7h
Record: https://patchnext.com/advisories/cve-2021-41098 (revision 1, source checked 26 Oct 2026, 15:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: nokogiri 1.12.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems nokogiri: affected <= 1.12.4; fixed in 1.12.5

## Suggested inspection (read-only)
- RubyGems nokogiri: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on nokogiri.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-2rr5-8q37-2w7h (GitHub-reviewed advisory GHSA-2rr5-8q37-2w7h lists affected ranges: RubyGems nokogiri >=0 <=1.12.4)

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