How severe is CVE-2026-57438?

No CVSS score has been assigned to CVE-2026-57438 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-57438?

CVE-2026-57438 affects the following packages: nokogiri (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2026-57438?

Update nokogiri to 1.19.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57438 is resolved across your whole dependency graph.

How do I detect CVE-2026-57438 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 CVE-2026-57438 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 CVE-2026-57438?

O3 pinpoints whether CVE-2026-57438 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 CVE-2026-57438 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-57438 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 type of vulnerability is CVE-2026-57438?

CVE-2026-57438 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 CVE-2026-57438 published, and has it been updated?

CVE-2026-57438 was published on June 25, 2026 and was last updated on July 15, 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

CVE-2026-57438

Nokogiri: Possible Use-After-Free in XInclude Processing

Also known asGHSA-wfpw-mmfh-qq69

Published

Jun 25, 2026

Updated

Jul 15, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

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

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, XInclude substitution performed by Nokogiri::XML::Node#do_xinclude replaced each xi:include in place, freeing the include node along with its children (such as xi:fallback and its descendants) and any namespaces declared on them. If an application had already exposed one of those nodes or namespaces to Ruby, the corresponding Ruby object was left pointing at freed memory. Using the object could result in invalid reads or writes to memory. This vulnerability is fixed in 1.19.4.

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 CVE-2026-57438 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 CVE-2026-57438 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 CVE-2026-57438. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, XInclude substitution performed by Nokogiri::XML::Node#do_xinclude replaced each <xi:include> in place, freeing the include node along with its children (such as <xi:fallback> and its descendants) and any namespaces declared on them. If an application had already exposed one of those nodes or namespaces to Ruby, the corresponding Ruby object was left pointing at freed memory. Using the object could result in invalid reads or writes to memory. This vulnerability is fixed in 1.19.4.

O3 Security · Impact-Aware SCA

Is CVE-2026-57438 in your dependencies?

O3 detects CVE-2026-57438 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works