{"id":"GHSA-p67v-3w7g-wjg7","title":"Nokogiri: Possible Use-After-Free when directly using `NokogirI::XML::XPathContext` beyond document lifetime","summary":"Nokogiri: Possible Use-After-Free when directly using `NokogirI::XML::XPathContext` beyond document lifetime","severity":"low","cwe":["CWE-416"],"vendor":"nokogiri","product":"nokogiri","affected":["nokogiri < 1.19.4"],"patched":["nokogiri 1.19.4"],"published":"2026-06-19","updated":"2026-06-19","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-p67v-3w7g-wjg7","references":[{"url":"https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-p67v-3w7g-wjg7"},{"url":"https://github.com/advisories/GHSA-p67v-3w7g-wjg7"}],"tags":["ghsa","rubygems"],"ingestedAt":"2026-06-22T15:52:21.089Z","ecosystem":"rubygems","slug":"GHSA-p67v-3w7g-wjg7","body":"## Overview\n\n### Summary\n\n`Nokogiri::XML::XPathContext` did not keep its source document alive for garbage collection. If an `XPathContext` outlived its document and the document was collected, evaluating an XPath expression could read invalid memory and potentially segfault.\n\nThis is only reachable when application code constructs an `XPathContext` directly and lets the document become unreachable while continuing to use the context. The normal `Document#xpath`, `#css`, and related search methods are not affected, and it is not triggerable by malicious document input.\n\nNokogiri 1.19.4 makes `XPathContext` keep its source document alive for as long as the context exists.\n\nOnly the CRuby implementation is affected. JRuby is not affected.\n\n### Severity\n\nThe Nokogiri maintainers have evaluated this as low severity. Reaching it requires an unusual API-usage pattern that does not arise during normal use. The application must construct an `XML::XPathContext` directly and continue using it after allowing its source document to be garbage-collected. Nokogiri 1.19.4 makes this pattern safe with no change to the public API. The context now keeps its source document alive for as long as it exists.\n\n### Mitigation\n\nUpgrade to Nokogiri 1.19.4 or later.\n\nAs a workaround, ensure the source document remains referenced for as long as any `XPathContext` created from it is in use. The standard `Document#xpath`, `#css`, and related search methods already do this and are unaffected.\n\n### Credit\n\nThis issue was responsibly reported by Zheng Yu from depthfirst.com.\n\n## Affected packages\n\n- `nokogiri < 1.19.4`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `nokogiri 1.19.4`","depth":"sunlit","depthScore":14,"depthScoreParts":{"impact":13.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}