CVE-2026-57235 Nokogiri: Possible Out-of-Bounds Read in `Nokogiri::XML::NodeSet#[]`

What is CVE-2026-57235?

CVE-2026-57235 is a medium-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::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.

Weakness: CWE-190, CWE-125

Which versions are affected by CVE-2026-57235?

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

Products include Nokogiri Nokogiri.

How do I fix CVE-2026-57235?

Upgrade nokogiri to 1.19.4 or later.

Is CVE-2026-57235 being exploited?

There is no known exploitation of CVE-2026-57235 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-91083, BELL-CVE-2026-57235, CLEANSTART-2026-KN35051, DEBIAN-CVE-2026-57235, GHSA-5prr-v3j2-97mh, MINI-32f7-rfj3-qcvh and 8 more.