{"cve":"CVE-2016-9909","nvd":{"published":"2017-02-22T16:59:00.380","modified":"2026-06-17T00:56:45.983","status":"Modified","description":"The serializer in html5lib before 0.99999999 might allow remote attackers to conduct cross-site scripting (XSS) attacks by leveraging mishandling of the < (less than) character in attribute values.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["http://www.openwall.com/lists/oss-security/2016/12/06/5","http://www.openwall.com/lists/oss-security/2016/12/08/8","http://www.securityfocus.com/bid/95132","https://github.com/html5lib/html5lib-python/commit/9b8d8eb5afbc066b7fac9390f5ec75e5e8a7cab7","https://github.com/html5lib/html5lib-python/issues/11"],"products":["html5lib:html5lib"],"source":"nvd","synced_at":"2026-10-19T20:41:54.846948762+00:00"},"epss":{"cve":"CVE-2016-9909","score":0.0216,"percentile":0.82209,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-v9v9-xffq-rwr4","url":"https://osv.dev/vulnerability/GHSA-v9v9-xffq-rwr4","summary":"Improper Neutralization of Input During Web Page Generation in html5lib","modified":"2024-09-20T21:43:02.859762Z","packages":[{"ecosystem":"PyPI","name":"html5lib","purl":"pkg:pypi/html5lib","ranges":["<0.999999999"],"fixed":["0.999999999"]}]},{"id":"PYSEC-2017-14","url":"https://osv.dev/vulnerability/PYSEC-2017-14","summary":"","modified":"2023-11-08T03:58:39.393067Z","packages":[{"ecosystem":"PyPI","name":"html5lib","purl":"pkg:pypi/html5lib","ranges":["<0.999999999"],"fixed":["0.999999999"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}