Information disclosure in Sensiolabs Symfony

CVE-2021-21424

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.

Vulnerability class: Information Disclosure

EPSS: 0.017 (75.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-21424?
CVE-2021-21424 is a medium-severity vulnerability in Sensiolabs Symfony, classified under Information Disclosure. CVSS score: 5.3/10. Published 2021-05-13.
How severe is CVE-2021-21424?
Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2021-21424 known to be exploited?
5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.