CVE-2026-57434 Nokogiri: Null Pointer Dereference calling methods on uninitialized wrapper classes

What is CVE-2026-57434?

CVE-2026-57434 is a low-severity vulnerability in sparklemotion nokogiri, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-476

Which versions are affected by CVE-2026-57434?

2 open source packages ship an affected version, including nokogiri. It affects 1 product.

Products include Nokogiri Nokogiri.

How do I fix CVE-2026-57434?

Upgrade nokogiri to 1.19.4 or later.

Is CVE-2026-57434 being exploited?

There is no known exploitation of CVE-2026-57434 in the wild and no public exploit code.

Other vulnerabilities in sparklemotion nokogiri

• CVE-2026-79770 Nokogiri before 1.19.3 ReDoS via CSS selector tokenizer High 8.7
• CVE-2022-23476 Unchecked return value from xmlTextReaderExpand in Nokogiri High 7.5
• CVE-2021-41098 Improper Restriction of XML External Entity Reference (XXE) in Nokogiri on JRuby High 7.5
• CVE-2012-6685 Nokogiri is vulnerable to XML External Entity (XXE) attack High 7.5
• CVE-2026-79771 Nokogiri before 1.19.3 Memory Leak via XSLT Transform Medium 6.9

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-91074, BELL-CVE-2026-57434, CLEANSTART-2026-OO68399, DEBIAN-CVE-2026-57434, GHSA-9cv2-cfxc-v4v2, MINI-5386-c8wp-2w9m and 8 more.