CVE-2026-57235
Description
A flaw was found in Nokogiri, an XML and HTML library for Ruby. This vulnerability allows an attacker to trigger an out-of-bounds read by providing a specially crafted large negative index to certain methods. This can lead to a denial of service (DoS) by crashing the application on CRuby, or by returning incorrect data on JRuby.
Statement
Red Hat ships Nokogiri as a dependency in several products (Satellite, 3scale API Management, RHEL BuildRoot). The vulnerable code path requires an attacker to supply a specially crafted large negative integer index to Nokogiri::XML::NodeSet#[] or #slice. Typically, NodeSet indices are not directly exposed to untrusted user input, which limits the practical exploitability of this flaw. On CRuby (used in Red Hat products), exploitation results in a process crash (denial of service) due to an out-of-bounds read, but does not lead to information disclosure or code execution.
Mitigation
There is no mitigation for this flaw other than upgrading to Nokogiri 1.19.4 or later. If upgrading is not immediately possible, review application code to ensure that untrusted user input is not passed as an index to `Nokogiri::XML::NodeSet#[]` or `#slice` methods.
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 | 5.9 | 8.2 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | Low | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Red Hat CVSS v3 Score Explanation
AC:H — exploitation requires attacker-controlled integer passed to NodeSet#[]; not a default usage pattern. Upstream maintainers rate as medium severity.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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