Answer in brief
CVE-2026-57234 records a Low severity (CVSS 2.6) vulnerability in Nokogiri: XML::Schema on JRuby allows network requests when NONET is set, bypassing CVE-2020-26247. The current sources do not mark it as known exploited. The current feed maps nokogiri (rubygems), nokogiri (rubygems). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 2.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps nokogiri (rubygems), nokogiri (rubygems). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| nokogirirubygems | <1.19.4 | 1.19.4 |
| nokogirirubygems | >=0 <1.19.4 | 1.19.4 |
Published upstream
Jun 19, 2026
Evidence: source:osv:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Jun 19, 2026
### Summary The `NONET` parse option, which Nokogiri turns on by default for `Nokogiri::XML::Schema` (see [CVE-2020-26247](https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-vr8q-g5c7-m54m)), 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. Nokogiri 1.19.4 replaces the scheme denylist with an allowlist. When `NONET` is enabled, only local resources (a `file:` scheme, or a relative or absolute path with no scheme) are resolved, and every network scheme is blocked, case-insensitively. This brings the JRuby behavior in line with CRuby. Only the JRuby implementation is affected. CRuby is not affected, because libxml2's `xmlNoNetExternalEntityLoader` blocks all network schemes at the I/O layer regardless of scheme or case. ### Severity The Nokogiri maintainers have evaluated this as low severity (CVSS 2.6, `CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N`). It is a bypass of CVE-2020-26247, which was scored the same way. ### Mitigation Upgrade to Nokogiri 1.19.4 or later. There are no known workarounds for affected versions. This change properly enforces `NONET` on JRuby, which is a breaking change for any code that (perhaps unknowingly) relied on the previous behavior to load network resources with default parse options. If you trust your input and want to allow external resources to be accessed over the network, you can explicitly disable `NONET`, exactly as documented for CVE-2020-26247: 1. Ensure the input is trusted. Do not enable this option for untrusted input. 2. Pass a `Nokogiri::XML::ParseOptions` with the `NONET` flag turned off: ``` ruby # allows resources to be accessed over the network for trusted input schema = Nokogiri::XML::Schema.new(trusted_schema, Nokogiri::XML::ParseOptions.new.nononet) ``` ### References - Bypass of: https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-vr8q-g5c7-m54m ### Credit This issue was responsibly reported by @bilerden.
Quoted source text, attributed separately from HOL analysis.