{"action":"Upgrade s9y/serendipity to 2.6.0 or later.","affected":[{"fixed":"2.6.0","introduced":"0"}],"component":"s9y/serendipity","cve_ids":["CVE-2026-39963"],"ecosystem":"Packagist","epss":0.00224,"exploited":false,"fixed_versions":["2.6.0"],"ghsa_id":"GHSA-4m6c-649p-f6gf","id":"tcs_01M5KEV3X76E690WTE0DJWSFZK","modified_at":"2026-04-15T21:35:53.816830Z","published_at":"2026-04-14T22:32:29Z","references":["https://osv.dev/vulnerability/GHSA-4m6c-649p-f6gf","https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf","https://nvd.nist.gov/vuln/detail/CVE-2026-39963","https://github.com/s9y/Serendipity","https://github.com/s9y/Serendipity/releases/tag/2.6.0"],"severity":{"label":"medium","score":6.9},"sources":[{"source":"osv","source_id":"GHSA-4m6c-649p-f6gf","url":"https://osv.dev/vulnerability/GHSA-4m6c-649p-f6gf"}],"summary":"Serendipity has a Host Header Injection allows authentication cookie scoping to attacker-controlled domain in functions_config.inc.php"}