CVE-2016-4423
HIGH7.5EPSS 1.4%Symphony Denial of Service Via Overlong Usernames
Published: 5/17/2022Modified: 5/27/2026
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.
Affected packages (4)
- Debian/symfonyfrom 0, < 2.8.6+dfsg-1
- Packagist/symfony/security>= 2.3.0, < 2.3.41
- Packagist/symfony/security-http>= 2.3.0, < 2.3.41
- Packagist/symfony/symfony>= 2.3.0, < 2.3.41
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (10)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2016-4423
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2016-4423
- PATCHhttps://github.com/symfony/symfony
- WEBhttps://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security/CVE-2016-4423.yaml
- WEBhttps://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-http/CVE-2016-4423.yaml
- WEBhttps://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2016-4423.yaml
- WEBhttps://github.com/symfony/symfony/pull/18733
- WEBhttps://symfony.com/blog/cve-2016-4423-large-username-storage-in-session
- WEBhttps://symfony.com/cve-2016-4423
- WEBhttp://www.debian.org/security/2016/dsa-3588