ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2016-4423

The attemptAuthentication function in Component/Security/Http/Firewall/UsernamePasswordFormAuthenticationListener.php in Symfony before 2.3.41, 2.7.x before 2.7.13, 2.…

Published Jun 1, 2016 · catalog updated Jun 17, 2026 · the affected product

Last checked Nov 8, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2016-4423. EPSS is 1.86%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.86%
Remediation
Version ranges on file
Affected products
cpe sensiolabs/symfony

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe sensiolabs/symfony2.7.0
  • cpe sensiolabs/symfony2.7.1
  • cpe sensiolabs/symfony2.7.2
  • cpe sensiolabs/symfony2.7.3
  • cpe sensiolabs/symfony2.7.4
  • cpe sensiolabs/symfony<= 2.3.40

How to fix CVE-2016-4423

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2016-4423. EPSS is 1.86%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with 2.7.0, 2.7.1, 2.7.2, 2.7.3, 2.7.4, <= 2.3.40. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-399. EPSS 1.86%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Symfony security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 1, 2016 · Monitored products — high

    Detected

    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 wi

  2. Jun 17, 2026 · Monitored products — high

    Updated

    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 wi

Sources

  • CVE.orgVulnerability recordCVE-2016-4423

    Official CVE identifier

    cve.org
  • Monitored products — highVendor advisoryCVE-2016-4423

    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 wi

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 8, 2026
  • Monitored products — highNov 7, 2026