CVE-2026-57438
Description
A flaw was found in Nokogiri, an XML and HTML library for the Ruby programming language. When performing XInclude substitutions, the library prematurely frees memory associated with nodes and namespaces. If an application has exposed these freed objects to Ruby, a local attacker could potentially trigger invalid reads or writes to memory. This memory corruption could lead to information disclosure or denial of service.
Statement
A flaw was found in Nokogiri, an XML and HTML library for the Ruby programming language. When performing XInclude substitution via Nokogiri::XML::Node#do_xinclude, the library frees memory associated with replaced xi:include nodes, their children (including xi:fallback), and declared namespaces. If an application has already exposed one of these nodes or namespaces to Ruby, the corresponding Ruby object points to freed memory, which could result in invalid memory reads or writes.
Red Hat products ship Nokogiri as a dependency of several components. The impact on Red Hat products is rated Moderate because exploitation requires the application to both perform XInclude substitution and separately retain references to nodes or namespaces within the substituted elements — a combination that is uncommon in typical usage patterns. This vulnerability only affects CRuby; JRuby is not affected.
This issue is fixed in Nokogiri version 1.19.4.
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.2 | 6.6 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | Low | Low | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
