CVE-2016-4423

mediumpriority · track · 31EPSS 0.019 · 79 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.86% (79th) EPSS

CVSS 5 · medium

Is it mine?

40 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

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

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.07.5highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.07.5highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · OSV

v3.06.9mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-399USprimary

affected products (40)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
debian debian linux= 8.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
sensiolabs symfony≤ 2.3.40nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.0nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.1nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.10nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.11nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.12nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.2nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.3nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.4nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.5nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.6nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.7nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.8nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.7.9nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.8.0nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.8.1nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.8.2nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
sensiolabs symfony= 2.8.3nvdUScpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*

showing 20 of 40

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-whgv-8cg3-7hcmSymphony Denial of Service Via Overlong Usernames2022-05-17ghsa · osvUS
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.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2016-06-01modified 2026-06-17

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+3721 more

references (10)

External citations — patches, advisories, analysis.

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