CVE-2021-21424 Prevent user enumeration using Guard or the new Authenticator-based Security

2021-05-1300:00:00

CWE-200

GitHub_M

www.cve.org

cve-2021-21424

symfony framework

user enumeration

guard

authenticator-based security

php

permissions

switch users functionality

patch

branch 3.4

CVSS3

5.3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

AI Score

5.8

Confidence

High

EPSS

0.001

Percentile

47.8%

JSON

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. The ability to enumerate users was possible without relevant permissions due to different handling depending on whether the user existed or not when attempting to use the switch users functionality. We now ensure that 403s are returned whether the user exists or not if a user cannot switch to a user or if the user does not exist. The patch for this issue is available for branch 3.4.

CNA Affected

[
  {
    "vendor": "symfony",
    "product": "symfony",
    "versions": [
      {
        "version": ">= 2.8.0, < 3.4.48",
        "status": "affected"
      },
      {
        "version": ">= 4.0.0, < 4.4.23",
        "status": "affected"
      },
      {
        "version": ">= 5.0.0, < 5.2.8",
        "status": "affected"
      }
    ]
  }
]