Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri contains a bug when calling certain methods on allocated-but-uninitialized native wrapper classes that inherit from Nokogiri::XML::Node. This caused a NULL pointer dereference that could crash the process. This vulnerability is fixed in 1.19.4.

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4,
    calling Document#encoding= with an invalid encoding (e.g., a non-string, or a string containing a null
    byte) raises an exception, but only after freeing the document's current encoding string without replacing
    it. The document is left referencing freed memory, so the next call to Document#encoding reads invalid
    memory, which can cause a segfault or leak freed bytes into a Ruby String. Affects the CRuby (libxml2)
    implementation only; JRuby is not affected. This vulnerability is fixed in 1.19.4. (CVE-2026-57236)

  - Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, the
    NONET parse option, which Nokogiri turns on by default for Nokogiri::XML::Schema (see CVE-2020-26247), was
    not correctly enforced on the JRuby implementation. As a result, a schema parsed with default options
    could still cause external resources to be fetched over the network, potentially enabling SSRF or XXE
    attacks. This vulnerability is fixed in 1.19.4. (CVE-2026-57234)

  - 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. (CVE-2026-57235)

  - Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4,
    Nokogiri contains a bug when calling certain methods on allocated-but-uninitialized native wrapper classes
    that inherit from Nokogiri::XML::Node. This caused a NULL pointer dereference that could crash the
    process. This vulnerability is fixed in 1.19.4. (CVE-2026-57434)

An update of the rubygem package has been released.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4,     Nokogiri contains a bug when calling certain methods on allocated-but-uninitialized native wrapper classes     that inherit from Nokogiri::XML::Node. This caused a NULL pointer dereference that could crash the     process. This vulnerability is fixed in 1.19.4. (CVE-2026-57434)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
478655	Alpine: ruby-nokogiri: security update to 1.19.4-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	Local	medium
478655	Alpine: ruby-nokogiri: security update to 1.19.4-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	Local	medium
375140	Photon OS 5.0: Rubygem PHSA-2026-5.0-90-1031	Nessus	PhotonOS Local Security Checks	Local	high
332554	Photon OS 5.0: Rubygem PHSA-2026-5.0-91-0911	Nessus	PhotonOS Local Security Checks	Local	medium
324558	Photon OS 5.0: Rubygem PHSA-2026-5.0-0911	Nessus	PhotonOS Local Security Checks	Local	medium
323619	Linux Distros Unpatched Vulnerability : CVE-2026-57434	Nessus	Misc.	Local	medium

Detections

Analytics

CVE-2026-57434

medium

Tenable Plugins

medium

medium

high

medium

medium

medium