{"action":"Upgrade craftcms/cms to 4.17.3 or later.","affected":[{"fixed":"4.17.3","introduced":"4.15.3"},{"fixed":"5.9.7","introduced":"5.7.5"}],"component":"craftcms/cms","cve_ids":["CVE-2026-31859"],"ecosystem":"Packagist","epss":0.00192,"exploited":false,"fixed_versions":["4.17.3","5.9.7"],"ghsa_id":"GHSA-fvwq-45qv-xvhv","id":"tcs_01M5KF232BWAM0E9037PGQXH2B","modified_at":"2026-03-13T10:56:24.729727Z","published_at":"2026-03-11T00:26:13Z","references":["https://osv.dev/vulnerability/GHSA-fvwq-45qv-xvhv","https://github.com/craftcms/cms/security/advisories/GHSA-fvwq-45qv-xvhv","https://nvd.nist.gov/vuln/detail/CVE-2026-31859","https://github.com/craftcms/cms/commit/cc9921c14897ee2b592a431c2356af8a04ce4cfe","https://github.com/craftcms/cms"],"severity":{"label":"medium","score":6.1},"sources":[{"source":"osv","source_id":"GHSA-fvwq-45qv-xvhv","url":"https://osv.dev/vulnerability/GHSA-fvwq-45qv-xvhv"},{"source":"nvd","source_id":"CVE-2026-31859","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31859"}],"summary":"CraftCMS vulnerable to reflective XSS via incomplete return URL sanitization"}