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CVE-2016-4423
The attemptAuthentication function in Component/Security/Http/Firewall/UsernamePasswordFormAuthenticationListener.php in Symfony before…
High7.5EPSS 1.9%
- Published
- Updated
- Reserved
- Assigned by
- mitre
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.0 | High7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.9% · top 21% of all CVEs (3 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
n/a
- affected n/a
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Packagistsymfony/securityGHSA-whgv-8cg3-7hcm (opens in a new tab)
- Packagistsymfony/security-httpGHSA-whgv-8cg3-7hcm (opens in a new tab)
- Packagistsymfony/symfonyGHSA-whgv-8cg3-7hcm (opens in a new tab)
References (3)
- https://symfony.com/blog/cve-2016-4423-large-username-storage-in-session (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/symfony/symfony/pull/18733 (opens in a new tab)x_refsource_CONFIRMx_transferred
- DSA-3588 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-whgv-8cg3-7hcm (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2016-4423)Record last updated .