Medium [CVE-2026-57235] Denial of Service via out-of-bounds read
This medium-severity Red Hat Linux advisory covers CVE-2026-57235 affecting Red Hat 3scale API Management Platform 2, Red Hat Satellite 6.
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Summary
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::NodeSet#[] (and its alias #slice) checked the requested index against the node set's bounds using a 32-bit-truncated copy of the index.
A large negative index could pass the check and then be used at full width, reading outside the node set's storage. On CRuby this is an out-of-bounds read that typically crashes the process; on JRuby it is not memory-unsafe but returns an incorrect node.
This vulnerability is fixed in 1.19.4. 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. 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.
- < 1.19.4
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
Mitigation checklist
- 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.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
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