Vulnerability DatabaseCVE-2021-21424
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CVE-2021-21424
Published:May 13, 2021
Updated:October 11, 2026
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.
Affected Packages
symfony/security-core (PHP):
Affected version(s) >=v2.8.0 <v3.4.48
Fix Suggestion:
Update to version v3.4.48
symfony/security-guard (PHP):
Affected version(s) >=v5.0.0 <v5.2.8
Fix Suggestion:
Update to version v5.2.8
symfony/symfony (PHP):
Affected version(s) >=v4.0.0 <v4.4.24
Fix Suggestion:
Update to version v4.4.24
symfony/security-core (PHP):
Affected version(s) >=v4.0.0 <v4.4.23
Fix Suggestion:
Update to version v4.4.23
lexik/jwt-authentication-bundle (PHP):
Affected version(s) >=v2.0.0 <v2.10.7
Fix Suggestion:
Update to version v2.10.7
symfony/security-core (PHP):
Affected version(s) >=v5.0.0 <v5.2.8
Fix Suggestion:
Update to version v5.2.8
symfony/security (PHP):
Affected version(s) >=v2.8.0 <v3.4.49
Fix Suggestion:
Update to version v3.4.49
symfony/symfony (PHP):
Affected version(s) >=v5.0.0 <v5.2.9
Fix Suggestion:
Update to version v5.2.9
symfony/security-guard (PHP):
Affected version(s) >=v4.0.0 <v4.4.23
Fix Suggestion:
Update to version v4.4.23
symfony/maker-bundle (PHP):
Affected version(s) >=v1.30.0 <v1.31.1
Fix Suggestion:
Update to version v1.31.1
symfony/symfony (PHP):
Affected version(s) >=v2.8.0 <v3.4.49
Fix Suggestion:
Update to version v3.4.49
symfony/security-http (PHP):
Affected version(s) >=v5.1.0 <v5.2.8
Fix Suggestion:
Update to version v5.2.8
symfony/maker-bundle (PHP):
Affected version(s) >=1.27.0 <v1.29.2
Fix Suggestion:
Update to version v1.29.2
symfony/security-guard (PHP):
Affected version(s) >=v2.8.0 <v3.4.48
Fix Suggestion:
Update to version v3.4.48
lexik/jwt-authentication-bundle (PHP):
Affected version(s) >=v2.11.0 <v2.11.3
Fix Suggestion:
Update to version v2.11.3
symfony/security (PHP):
Affected version(s) >=v4.0.0 <v4.4.24
Fix Suggestion:
Update to version v4.4.24
Related Resources (24)
https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-http/CVE-2021-21424.yaml
https://github.com/FriendsOfPHP/security-advisories/blob/master/lexik/jwt-authentication-bundle/CVE-2021-21424.yaml
https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/maker-bundle/CVE-2021-21424.yaml
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VRUS2H2SSOQWNLBD35SKIWIDQEMV2PD3/
https://nvd.nist.gov/vuln/detail/CVE-2021-21424
https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-guard/CVE-2021-21424.yaml
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UC7BND775DVZDQT3RMGD2HVB2PKLJDJW/
https://github.com/symfony/symfony/security/advisories/GHSA-5pv8-ppvj-4h68
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UC7BND775DVZDQT3RMGD2HVB2PKLJDJW
https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security/CVE-2021-21424.yaml
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VRUS2H2SSOQWNLBD35SKIWIDQEMV2PD3
https://symfony.com/cve-2021-21424
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UC7BND775DVZDQT3RMGD2HVB2PKLJDJW
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KENRNLB3FYXYGDWRBH2PDBOZZKOD7VY4
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RH7TMM5CHQYBFFGXWRPJDPB3SKCZXI2M
https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2021-21424.yaml
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KENRNLB3FYXYGDWRBH2PDBOZZKOD7VY4/
https://lists.debian.org/debian-lts-announce/2023/07/msg00014.html
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VRUS2H2SSOQWNLBD35SKIWIDQEMV2PD3
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KENRNLB3FYXYGDWRBH2PDBOZZKOD7VY4
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RH7TMM5CHQYBFFGXWRPJDPB3SKCZXI2M/
https://github.com/symfony/symfony
https://github.com/symfony/symfony/commit/2a581d22cc621b33d5464ed65c4bc2057f72f011
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RH7TMM5CHQYBFFGXWRPJDPB3SKCZXI2M
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CVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
CVSS v2
Base Score:
5
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
Weakness Type (CWE)
Exposure of Sensitive Information to an Unauthorized Actor
CWE-200
Observable Discrepancy
CWE-203
EPSS
Base Score:
1.71