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🛡️ CVE-2026-57438 — nokogiri

🟢 CVSS 2.0 — Low ✅ No Known Exploit CWE-416 OSV
2.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Nokogiri: Possible Use-After-Free in XInclude Processing

Summary

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.

Nokogiri 1.19.4 substitutes each <xi:include> on a defensive copy by default, so the structures libxml2 frees are never the ones bound to live Ruby objects.

Only the CRuby implementation is affected; 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 parse a document without XInclude, traverse into an <xi:include> subtree to expose its nodes or namespaces to Ruby, and only then invoke XInclude processing. The common case, requesting XInclude at parse time, operates on a freshly parsed document whose nodes are not yet exposed to Ruby and is not affected. Nokogiri 1.19.4 makes this pattern safe by default and requires no change to application code.

Mitigation

Upgrade to Nokogiri 1.19.4 or later.

As a workaround for earlier versions, perform XInclude substitution at parse time (with the xinclude parse option) rather than calling #do_xinclude on a document that has already been traversed. A freshly parsed document has no nodes exposed to Ruby, so the substitution is safe.

Credit

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

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-57438 is classified as CWE-416: Use After Free. Memory is used after being released, so its contents may already belong to something else.

Affected software

CVE-2026-57438 is recorded against 1 package.

  • nokogiri (fixed in 1.19.4)

Timeline and source

Published on 19 June 2026 and last revised on 8 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
github.com (Package)

Other advisories for this package

nokogiri has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-416: Use After Free) in other software:

Details

Severity LOW
CVSS Score 2.0
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
CWE CWE-416
Public Exploit ✅ No
Source OSV
Published 2026-06-19
Updated 2026-08-20
Modified 2026-07-08
Fix URL N/A

Affected Packages

Software From version Fixed in
nokogiri — 1.19.4

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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