CVE-2022-23476 is a high-severity (CVSS 7.5) CWE-252 vulnerability in nokogiri. A fix is available for nokogiri — see the affected versions and patch details below.
Unchecked return value from xmlTextReaderExpand in Nokogiri
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-23476.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2022-23476 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
nokogiriReal-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 1.13.8, 1.13.9 fails to check the return value from xmlTextReaderExpand in the method Nokogiri::XML::Reader#attribute_hash. This can lead to a null pointer exception when invalid markup is being parsed.
For applications using XML::Reader to parse untrusted inputs, this may potentially be a vector for a denial of service attack.
Mitigation
Upgrade to Nokogiri >= 1.13.10.
Users may be able to search their code for calls to either XML::Reader#attributes or XML::Reader#attribute_hash to determine if they are affected.
Severity
The Nokogiri maintainers have evaluated this as High Severity 7.5 (CVSS3.1).
References
Credit
This vulnerability was responsibly reported by @davidwilemski.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | nokogiri | ≥ 1.13.8&&< 1.13.10 | 1.13.10bundle update nokogiri --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
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.
Fix
Update nokogiri to 1.13.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-23476 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-23476 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-23476. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2022-23476 in your dependencies?
O3 Security finds CVE-2022-23476 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.