How severe is GHSA-9cv2-cfxc-v4v2?

No CVSS score has been assigned to GHSA-9cv2-cfxc-v4v2 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-9cv2-cfxc-v4v2?

GHSA-9cv2-cfxc-v4v2 affects the following packages: nokogiri (RubyGems). Ecosystems affected: RubyGems.

How do I fix GHSA-9cv2-cfxc-v4v2?

Update nokogiri to 1.19.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9cv2-cfxc-v4v2 is resolved across your whole dependency graph.

How do I detect GHSA-9cv2-cfxc-v4v2 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 GHSA-9cv2-cfxc-v4v2 if there is no patch (or I can't update yet)?

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.

Is GHSA-9cv2-cfxc-v4v2 actively exploited in the wild?

No public exploit code has been indexed for GHSA-9cv2-cfxc-v4v2 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.

What is the EPSS score for GHSA-9cv2-cfxc-v4v2?

GHSA-9cv2-cfxc-v4v2 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 39th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-9cv2-cfxc-v4v2?

GHSA-9cv2-cfxc-v4v2 is classified as NULL Pointer Dereference (CWE-476). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-9cv2-cfxc-v4v2 published, and has it been updated?

GHSA-9cv2-cfxc-v4v2 was published on June 19, 2026 and was last updated on September 10, 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

Nokogiri: Null Pointer Dereference calling methods on uninitialized wrapper classesGHSA-9cv2-cfxc-v4v2

GHSA-9cv2-cfxc-v4v2 is a NULL Pointer Dereference vulnerability in nokogiri. A fix is available for nokogiri — see the affected versions and patch details below.

Also known asCVE-2026-57434

Published

Jun 19, 2026

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 GHSA-9cv2-cfxc-v4v2.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs39th percentile — riskier than 39% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from 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 contains a bug when calling certain methods on allocated-but-uninitialized native wrapper classes that inherit from Nokogiri::XML::Node. This caused a NULL pointer dereference that could crash the process.

Nokogiri 1.19.4 checks for missing native data pointers and raises a RuntimeError.

JRuby is not affected.

Severity

The Nokogiri maintainers have evaluated this as low severity. This is only triggered by a programming error. It requires application code to call .allocate directly on a native-backed class and then invoke methods on the resulting uninitialized object. It cannot be triggered by untrusted input or through normal use of the public API.

Mitigation

Upgrade to Nokogiri 1.19.4 or later.

Avoid calling .allocate directly on Nokogiri native-backed classes. Use the documented constructors and factory methods instead.

Credit

This issue was responsibly reported by Zheng Yu from depthfirst.com.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`nokogiri`	all versions	1.19.4`bundle update nokogiri --conservative`

Affected Products

1 product · 1 configurations

Application

nokogirinokogiri

< 1.19.4

range

Detection & mitigation playbook

Open-source dependency

Detect
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 1.19.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9cv2-cfxc-v4v2 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.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

A flaw was found in Nokogiri, an open source XML and HTML library for Ruby. Calling certain methods on allocated-but-uninitialized native wrapper classes that inherit from Nokogiri::XML::Node triggers a NULL pointer dereference, crashing the process. An attacker who can control the construction of Nokogiri node…

Workaround published by Red Hat

There is no mitigation for this flaw other than updating to Nokogiri version 1.19.4 or later. As a workaround, ensure that untrusted input cannot trigger the construction of uninitialized native wrapper classes inheriting from Nokogiri::XML::Node.

Source: Red Hat security advisory for GHSA-9cv2-cfxc-v4v2 (CC BY 4.0)

Frequently Asked Questions

### Summary Nokogiri contains a bug when calling certain methods on allocated-but-uninitialized native wrapper classes that inherit from `Nokogiri::XML::Node`. This caused a NULL pointer dereference that could crash the process. Nokogiri 1.19.4 checks for missing native data pointers and raises a `RuntimeError`. JRuby is not affected. ### Severity The Nokogiri maintainers have evaluated this as low severity. This is only triggered by a programming error. It requires application code to call `.allocate` directly on a native-backed class and then invoke methods on the resulting uninitialize

O3 Security · Impact-Aware SCA

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