Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2016-2403

32
FAUCET Score

CVE-2016-2403 is a critical authentication bypass vulnerability affecting Symfony versions prior to 2.8.6 and 3.x prior to 3.0.6. This flaw allows remote attackers to gain unauthorized access by providing a valid username with an empty password, triggering an unauthenticated bind. With a CVSS score of 9.8, it poses a severe risk of complete compromise (confidentiality, integrity, and availability). Despite its critical severity, there is no evidence of active exploitation, publicly available exploit code, or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
2.8.0CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:2.8.0:*:*:*:*:*:*:*
2.8.1CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:2.8.1:*:*:*:*:*:*:*
2.8.2CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:2.8.2:*:*:*:*:*:*:*
2.8.3CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:2.8.3:*:*:*:*:*:*:*
2.8.4CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:2.8.4:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
2.93%
Probability of exploitation in next 30 days
EPSS Percentile
85.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0293 is in the 77th percentile among its peer group of 36,833 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

composerpatch availablevia ghsa
Product: symfony/security-coreFixed in: 2.8.6
composerpatch availablevia ghsa
Product: symfony/security-coreFixed in: 3.0.6
composerpatch availablevia ghsa
Product: symfony/securityFixed in: 2.8.6
composerpatch availablevia ghsa
Product: symfony/securityFixed in: 3.0.6
composerpatch availablevia ghsa
Product: symfony/symfonyFixed in: 2.8.6
composerpatch availablevia ghsa
Product: symfony/symfonyFixed in: 3.0.6

Vendor Advisories (1)

composerGHSA-wvj5-r78r-hhfqcritical

Symfony Authentication Bypass

May 14, 2022

References

debian.org / security/2018/dsa-4262
symfony.com / blog/cve-2016-2403-unauthorized-access-on-a-misconfigured-ldap-server-when-using-an-empty-password
Vendor Advisory
securityfocus.com / bid/96137
Third Party AdvisoryVDB Entry