Low [CVE-2026-57436] Denial of Service via heap use-after-free
This low-severity Red Hat Linux advisory covers CVE-2026-57436 affecting Red Hat 3scale API Management Platform 2, Red Hat Satellite 6.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root.
The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4.
This vulnerability occurs due to insufficient validation when setting the document's root element, allowing a malicious document to trigger a memory error. This can lead to a heap use-after-free, potentially causing the application to crash and resulting in a Denial of Service (DoS).
This could lead to application crashes and impact the availability of services that process untrusted XML or HTML content using Nokogiri. This is only triggered by a programming error.
Red Hat ships Nokogiri as a dependency in several products including Red Hat 3scale API Management Platform, Red Hat Satellite, and Red Hat Enterprise Linux buildroot packages. All affected product versions ship Nokogiri prior to the 1.19.4 fix.
This memory-safety issue affects only the CRuby implementation (libxml2). The JRuby implementation was not affected; the same input validation was added there for behavioral parity.
Is CVE-2026-57436 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-57436 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-57436?
Upgrade to a fixed release named by Red Hat:
- 1.19.4
Confirm against the vendor advisory before you patch.
- < 1.19.4
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
Mitigation checklist
- To mitigate this issue, applications that use Nokogiri to process untrusted XML or HTML documents should implement robust input validation and operate within a sandboxed environment. Restricting the application's ability to process arbitrary external content can reduce the risk of triggering the heap use-after-free vulnerability and prevent a denial of service.
Official advisory · high-confidence parse· fetched 14 days ago·verify at source
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