How severe is GHSA-5v8h-3h3q-446p?

No CVSS score has been assigned to GHSA-5v8h-3h3q-446p yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-5v8h-3h3q-446p?

GHSA-5v8h-3h3q-446p affects the following packages: nokogiri (RubyGems). Ecosystems affected: RubyGems.

How do I fix GHSA-5v8h-3h3q-446p?

Update nokogiri to 1.19.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5v8h-3h3q-446p is resolved across your whole dependency graph.

How do I detect GHSA-5v8h-3h3q-446p in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nokogiri. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-5v8h-3h3q-446p 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.

How does O3 Security protect against GHSA-5v8h-3h3q-446p?

O3 pinpoints whether GHSA-5v8h-3h3q-446p is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-5v8h-3h3q-446p actively exploited in the wild?

No public exploit code has been indexed for GHSA-5v8h-3h3q-446p 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-5v8h-3h3q-446p?

GHSA-5v8h-3h3q-446p has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 27th 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-5v8h-3h3q-446p?

GHSA-5v8h-3h3q-446p is classified as Use After Free (CWE-416). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-5v8h-3h3q-446p published, and has it been updated?

GHSA-5v8h-3h3q-446p was published on June 19, 2026 and was last updated on July 8, 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

GHSA-5v8h-3h3q-446p

GHSA-5v8h-3h3q-446p is a Use After Free vulnerability in nokogiri. O3 Security confirms whether GHSA-5v8h-3h3q-446p is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Nokogiri: Possible Use-After-Free when `Nokogiri::XML::Document#encoding=` raises an exception

Also known asCVE-2026-57236

Published

Jun 19, 2026

Updated

Jul 8, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

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-5v8h-3h3q-446p.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs27th percentile — riskier than 27% of all scored CVEsHighest risk

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.

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

Calling Document#encoding= with an invalid encoding (e.g., a non-string, or a string containing a null byte) raises an exception, but only after freeing the document's current encoding string without replacing it. The document is left referencing freed memory, so the next call to Document#encoding reads invalid memory, which can cause a segfault or leak freed bytes into a Ruby String.

Affects the CRuby (libxml2) implementation only; JRuby is not affected.

Severity

The Nokogiri maintainers have evaluated this as low severity. Reaching it requires an unusual API-usage pattern that does not arise during normal use. The application must pass an invalid encoding to Document#encoding=, rescue the resulting exception, and then continue using the same document. Nokogiri 1.19.4 makes this pattern safe with no change to the public API. The document no longer references freed memory after the exception is raised.

Mitigation

Upgrade to Nokogiri 1.19.4 or later.

If users are unable to upgrade, avoid passing attacker-controlled values to Document#encoding=. Applications that only assign developer-authored encodings are not directly exposed.

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

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nokogiri. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update nokogiri to 1.19.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5v8h-3h3q-446p 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 pinpoints whether GHSA-5v8h-3h3q-446p is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-5v8h-3h3q-446p. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

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 HatModerate

This flaw has an Important impact as Nokogiri's CRuby implementation in Red Hat products is vulnerable to a use-after-free when processing invalid encoding values. A remote unauthenticated attacker can trigger a segmentation fault causing denial of service, or leak freed memory contents into a Ruby String causing…

RHSA-2026:50223Red Hat Satellite 6.16 for RHEL 8 RHSA-2026:50222Red Hat Satellite 6.17 for RHEL 9 RHSA-2026:50263Red Hat Satellite 6.18 for RHEL 9 RHSA-2026:50221Red Hat Satellite 6.19 for RHEL 9

Frequently Asked Questions

### Summary Calling `Document#encoding=` with an invalid encoding (e.g., a non-string, or a string containing a null byte) raises an exception, but only after freeing the document's current encoding string without replacing it. The document is left referencing freed memory, so the next call to `Document#encoding` reads invalid memory, which can cause a segfault or leak freed bytes into a Ruby `String`. Affects the CRuby (libxml2) implementation only; JRuby is not affected. ### Severity The Nokogiri maintainers have evaluated this as low severity. Reaching it requires an unusual API-usage p

O3 Security · Impact-Aware SCA

Is GHSA-5v8h-3h3q-446p in your dependencies?

O3 detects GHSA-5v8h-3h3q-446p across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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