CVE-2026-40186: sanitize-html allowedTags Bypass via Entity-Decoded Text in nonTextTags Elements

April 16, 2026

Commit 49d0bb7 introduced a regression in sanitize-html that bypasses allowedTags enforcement for text inside nonTextTagsArray elements (textarea and option). Entity-encoded HTML inside these elements passes through the sanitizer as decoded, unescaped HTML, allowing injection of arbitrary tags including XSS payloads. This affects any application using sanitize-html that includes option or textarea in its allowedTags configuration.

References

github.com/advisories/GHSA-9mrh-v2v3-xpfm
github.com/apostrophecms/apostrophe/commit/7ca2d16237c72718ef7e5c7ae0458e6027ac4f64
github.com/apostrophecms/apostrophe/security/advisories/GHSA-9mrh-v2v3-xpfm
nvd.nist.gov/vuln/detail/CVE-2026-40186

Code Behaviors & Features

Detect and mitigate CVE-2026-40186 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Dependency Scanning using SBOM also detects vulnerabilities from proprietary advisories that this site does not include. Learn more about Dependency Scanning using SBOM →