Nokogiri vulnerabilities

The vulnerability in the Nokogiri library affects the protected copy helper used by Node#dup and #clone methods. It unwrapped the source argument as an xmlNode without a type check, causing an out-of-bounds read on xmlNs structure and process crash when a non-Node object (e.g. Namespace) was supplied. Version 1.19.4 adds a type check and raises TypeError.

A vulnerability in the Nokogiri library affects the `Nokogiri::XML::NodeSet#[]` method (and its alias `#slice`). The index check against the node set's bounds used a 32-bit-truncated copy of the index, allowing a large negative index to pass the check and then be used at full width, reading outside the node set's storage.

A vulnerability in the Nokogiri library allows calling `Document#encoding=` with an invalid encoding (e.g., a non-string or a string containing a null byte), which frees the document's current encoding string without replacing it. The document is left referencing freed memory, leading to a use-after-free condition on the next call.

The vulnerability in the Nokogiri library for JRuby causes the NONET option to be incorrectly enforced when parsing XML schemas. This allows an attacker to load external network resources, potentially leading to data leakage or SSRF attacks.

Nokogiri has a bug in methods called on allocated-but-uninitialized native wrapper classes inheriting from `Nokogiri::XML::Node`. This causes a NULL pointer dereference that could crash the process.

The vulnerability in the Nokogiri library causes `Nokogiri::XML::XPathContext` to not keep its source document alive for garbage collection. If an XPathContext outlives its document and the document is collected, evaluating an XPath expression could read invalid memory and potentially segfault.

Nokogiri's CRuby native extension could leave a Ruby wrapper pointing to freed memory when replacing the value of an XML attribute. If Ruby code had already accessed an attribute child node, `Nokogiri::XML::Attr#value=` could free the underlying native child node while the wrapper remains.

A vulnerability in the Nokogiri library allows a DTD node to be set as the document root, leading to a heap use-after-free during garbage collection or finalization. This results in an invalid memory read or potentially a segfault.

The vulnerability in the Nokogiri library affects the `Nokogiri::XML::Node#do_xinclude` method, which during XInclude processing removes `<xi:include>` nodes along with their children (e.g., `<xi:fallback>`) and declared namespaces. If an application previously accessed these nodes, unexpected behavior may occur.

Nokogiri before 1.18.3 contains a stack buffer overflow vulnerability in libxml2 when reporting DTD validation errors with long QName prefixes, and a use-after-free vulnerability during validation against untrusted XML Schemas. Attackers can trigger these vulnerabilities by providing malicious DTD content or untrusted XSD files to cause denial of service or potential code execution.

Nokogiri before 1.15.6 and 1.16.x before 1.16.2 (CRuby, when using the packaged libxml2) is affected by a use-after-free vulnerability in libxml2 (CVE-2024-25062) in the xmlTextReader module, which underlies Nokogiri::XML::Reader. When using the XML Reader interface with DTD validation and XInclude expansion enabled, processing a crafted XML document can lead to an xmlValidatePopElement use-after-free. Nokogiri 1.15.6 and 1.16.2 resolve this by upgrading the packaged libxml2 to 2.11.7 and 2.12.5 respectively. JRuby and installations using system libxml2 are not affected.

Nokogiri before 1.13.2 ships vendored libxml2 2.9.12 and libxslt 1.1.34, which are affected by two upstream CVEs. Via CVE-2021-30560 in libxslt, an application transforming XML with untrusted XSL stylesheets is vulnerable to a denial-of-service attack. Via CVE-2022-23308 in libxml2, an application parsing an untrusted document with parse option DTDVALID set to true and NOENT set to false may be vulnerable to denial of service, memory disclosure, or code execution.

Nokogiri versions before 1.19.1 fail to check the return value from xmlC14NExecute in the canonicalize method, returning an empty string on failure instead of raising an exception. Attackers can exploit this to bypass signature validation in downstream SAML libraries by providing invalid canonicalized XML that is incorrectly accepted as valid.

Nokogiri versions before 1.19.3 contain a memory leak in the XSLT Stylesheet transform method when processing Ruby strings containing null bytes. Attackers can exploit this by passing attacker-controlled input with null bytes to transform parameters, causing heap allocations to leak and enabling denial of service against long-running processes.

Nokogiri versions before 1.19.3 contain regular expression denial of service vulnerabilities in the CSS selector tokenizer affecting string-literal and identifier tokenization. Attackers can inject adversarial CSS selectors into methods like Node#css, Node#at_css, and Searchable#search to cause exponential regex backtracking and denial of service.

Nokogiri versions before 1.19.4 contain a possible invalid (out-of-bounds) memory read in the protected internal Node#initialize_copy_with_args helper behind Node#dup and #clone, which unwrapped its source argument as an xmlNode without a type check. If application code calls this protected method with a non-Node argument (e.g., a Namespace), it reads an xmlNs out of bounds, crashing the process. This is only triggerable by a programming error and cannot be triggered by untrusted input or normal use of the public API. Only CRuby is affected. Version 1.19.4 adds a type check and raises TypeError.

Nokogiri before 1.18.4 bundles a vulnerable version of libxslt (prior to 1.1.43) with two use-after-free vulnerabilities: CVE-2025-24855 and CVE-2024-55549. Processing crafted XSLT can trigger memory corruption. Nokogiri 1.18.4 upgrades libxslt to 1.1.43.

Nokogiri before 1.18.8 packages a vulnerable version of libxml2 (before 2.13.8) that contains a heap-based buffer under-read (CVE-2025-32415) in the xmlSchemaIDCFillNodeTables function in xmlschemas.c. The issue can be triggered when validating against an untrusted XML Schema, or when validating untrusted documents against trusted schemas that use xsd:keyref in combination with recursively defined types that have additional identity constraints.

Nokogiri versions before 1.16.5 bundle libxml2 2.12.6, which is affected by CVE-2024-34459 in libxml2's xmllint tool. Nokogiri 1.16.5 upgrades the bundled libxml2 to 2.12.7 to address this. Per the maintainers, there is no impact to Nokogiri users because Nokogiri does not provide or expose the xmllint tool where the issue occurs.

Nokogiri before 1.14.3 (CRuby implementation only, when using the packaged libxml2) bundles libxml2 v2.10.3, which is vulnerable to NULL pointer dereferences in XML Schema processing (CVE-2023-28484 and CVE-2023-28485). An attacker can supply a crafted XML schema to cause a segfault and denial of service.

Nokogiri versions before 1.13.5 contain an integer overflow vulnerability in packaged libxml2 buffer handling functions that allows attackers to cause out-of-bounds memory writes. Attackers can exploit this by crafting multi-gigabyte XML files to trigger buffer overflows resulting in information disclosure, data modification, or denial of service.

Nokogiri before 1.13.9 (CRuby implementation using packaged libraries) bundles libxml2 v2.9.14, which is affected by CVE-2022-40304 (data corruption / double-free) and CVE-2022-40303 (integer overflows). Processing crafted XML input may lead to denial of service or memory corruption.

Nokogiri before 1.11.4 (CRuby implementation only, when the packaged/vendored libxml2 is used) bundles libxml2 2.9.10, which is affected by multiple vulnerabilities addressed in libxml2 2.9.12, including a memory leak, heap-based buffer overflow, and out-of-bounds read. Processing crafted XML documents may lead to denial of service, information disclosure, or memory corruption.