{"cve":"CVE-2016-4423","nvd":{"published":"2016-06-01T22:59:02.457","modified":"2026-06-17T00:47:31.710","status":"Modified","description":"The attemptAuthentication function in Component/Security/Http/Firewall/UsernamePasswordFormAuthenticationListener.php in Symfony before 2.3.41, 2.7.x before 2.7.13, 2.8.x before 2.8.6, and 3.0.x before 3.0.6 does not limit the length of a username stored in a session, which allows remote attackers to cause a denial of service (session storage consumption) via a series of authentication attempts with long, non-existent usernames.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-399"],"references":["http://www.debian.org/security/2016/dsa-3588","https://github.com/symfony/symfony/pull/18733","https://symfony.com/blog/cve-2016-4423-large-username-storage-in-session","http://www.debian.org/security/2016/dsa-3588","https://github.com/symfony/symfony/pull/18733"],"products":["debian:debian_linux","sensiolabs:symfony"],"source":"nvd","synced_at":"2026-10-19T20:38:51.654415212+00:00"},"epss":{"cve":"CVE-2016-4423","score":0.01862,"percentile":0.79257,"date":"2026-10-31"},"kev":null,"osv":[],"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."]}