{"id":"CVE-2026-79771","aliases":["GHSA-v2fc-qm4h-8hqv"],"url":"https://o3.security/vulnerability/CVE-2026-79771","summary":"Nokogiri before 1.19.3 Memory Leak via XSLT Transform","details":"## Summary\n\nNokogiri's `Nokogiri::XSLT::Stylesheet#transform` leaks a small heap allocation when passed a Ruby string parameter containing a null byte.\n\nFor applications that pass attacker-controlled input through `XSLT.transform` parameters, this may be a vector for a denial of service attack against long-running processes.\n\n\n## Mitigation\n\nUpgrade to Nokogiri `>= 1.19.3`.\n\nUsers may also be able to mitigate this issue without upgrading by validating untrusted transform parameters before passing them to `Nokogiri::XSLT::Stylesheet#transform`.\n\n\n## Severity\n\nThe Nokogiri maintainers have evaluated this as **Moderate Severity**, CVSS 5.3.\n\nEach leaked allocation is approximately 24–32 bytes, so meaningful memory growth requires sustained attacker-controlled traffic at high call rates. The bug does not cause memory corruption, information disclosure, or any change in the behavior of the transform itself, and the string-handling exception is raised as expected.\n\nApplications that do not pass raw attacker-controlled bytes to XSLT parameters are unlikely to be affected in practice.\n\n\n## Resources\n\n- [CWE-401: Missing Release of Memory after Effective Lifetime](https://cwe.mitre.org/data/definitions/401.html)\n\n\n## Credit\n\nThis vulnerability was responsibly reported by @Captainjack-kor.","published":"2026-08-25T15:16:03.736Z","modified":"2026-10-28T02:31:13.976132241Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"RubyGems","name":"nokogiri","fixedVersion":"1.19.3"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/79xxx/CVE-2026-79771.json"},{"type":"ADVISORY","url":"https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-v2fc-qm4h-8hqv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-79771"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/nokogiri-before-memory-leak-via-xslt-transform"},{"type":"PACKAGE","url":"https://github.com/sparklemotion/nokogiri"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:13.976132241Z"}}