{"cve":"CVE-2026-40186","nvd":{"published":"2026-04-15T21:17:27.523","modified":"2026-10-26T21:10:00.170","status":"Analyzed","description":"ApostropheCMS is an open-source Node.js content management system. A regression introduced in commit 49d0bb7, included in versions 2.17.1 of the ApostropheCMS-maintained sanitize-html package bypasses allowedTags enforcement for text inside nonTextTagsArray elements (textarea and option). ApostropheCMS version 4.28.0 is affected through its dependency on the vulnerable sanitize-html version. The code at packages/sanitize-html/index.js:569-573 incorrectly assumes that htmlparser2 does not decode entities inside these elements and skips escaping, but htmlparser2 10.x does decode entities before passing text to the ontext callback. As a result, entity-encoded HTML is decoded by the parser and then written directly to the output as literal HTML characters, completely bypassing the allowedTags filter. An attacker can inject arbitrary tags including XSS payloads through any allowed option or textarea element using entity encoding. This affects non-default configurations where option or textarea are included in allowedTags, which is common in form builders and CMS platforms. This issue has been fixed in version 2.17.2 of sanitize-html and 4.29.0 of ApostropheCMS.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://github.com/apostrophecms/apostrophe/commit/7ca2d16237c72718ef7e5c7ae0458e6027ac4f64","https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-9mrh-v2v3-xpfm"],"products":["apostrophecms:apostrophecms","apostrophecms:sanitize-html"],"source":"nvd","synced_at":"2026-10-26T21:38:48.864438205+00:00"},"epss":{"cve":"CVE-2026-40186","score":0.00248,"percentile":0.15999,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-9mrh-v2v3-xpfm","url":"https://osv.dev/vulnerability/GHSA-9mrh-v2v3-xpfm","summary":"sanitize-html allowedTags Bypass via Entity-Decoded Text in nonTextTags Elements","modified":"2026-04-16T21:26:28.221563Z","packages":[{"ecosystem":"npm","name":"sanitize-html","purl":"pkg:npm/sanitize-html","ranges":[">=2.17.2 <2.17.3"],"fixed":["2.17.3"]}]}],"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."]}