How severe is CVE-2021-47996?

No CVSS score has been assigned to CVE-2021-47996 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2021-47996?

CVE-2021-47996 affects the following packages: nokogiri (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2021-47996?

Update nokogiri to 1.11.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-47996 is resolved across your whole dependency graph.

How do I detect CVE-2021-47996 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nokogiri, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-47996 if there is no patch (or I can't update yet)?

Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Is CVE-2021-47996 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-47996 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2021-47996 published, and has it been updated?

CVE-2021-47996 was published on August 25, 2026 and was last updated on September 3, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

Not in CISA KEV

CVE-2021-47996 — nokogiri

Fix: GNOME/libxml2@0e1a49c

CVE-2021-47996 is a remote code execution vulnerability in nokogiri. A fix is available for nokogiri — see the affected versions and patch details below.

Nokogiri updates packaged dependency on libxml2 from 2.9.10 to 2.9.12

Also known asGHSA-7rrm-v45f-jp64

Published

Aug 25, 2026

Updated

Sep 3, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 3, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

💎nokogiri

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Nokogiri v1.11.4 updates the vendored libxml2 from v2.9.10 to v2.9.12 which addresses:

CVE-2019-20388 (Medium severity)
CVE-2020-24977 (Medium severity)
CVE-2021-3517 (Medium severity)
CVE-2021-3518 (Medium severity)
CVE-2021-3537 (Low severity)
CVE-2021-3541 (Low severity)

Note that two additional CVEs were addressed upstream but are not relevant to this release. CVE-2021-3516 via xmllint is not present in Nokogiri, and CVE-2020-7595 has been patched in Nokogiri since v1.10.8 (see #1992).

Please note that this advisory only applies to the CRuby implementation of Nokogiri < 1.11.4, and only if the packaged version of libxml2 is being used. If you've overridden defaults at installation time to use system libraries instead of packaged libraries, you should instead pay attention to your distro's libxml2 release announcements.

Mitigation

Upgrade to Nokogiri >= 1.11.4.

Impact

I've done a brief analysis of the published CVEs that are addressed in this upstream release. The libxml2 maintainers have not released a canonical set of CVEs, and so this list is pieced together from secondary sources and may be incomplete.

All information below is sourced from security.archlinux.org, which appears to have the most up-to-date information as of this analysis.