CVE-2021-21424
Prevent user enumeration using Guard or the new Authenticator-based Security
- Published
- May 13, 2021
- Updated
- Aug 3, 2024
- Assigning CNA
- GitHub_M
- Evidence observed
- Aug 7, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NLow · next 30 days
- Percentile
- 76.0%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
2- CVE-2021-21424Exploit
El WebProfiler de Symfony expone rutas internas del servidor si no está deshabilitado en producción
- Symfony-CVE-Scanner-PoC-Scanner
CVE-2021-21424 - CRLF Injection - CVE-2021-41268 - Host Header Injection - CVE-2022-24894 - WebProfiler abierto - CVE-2019-10909 - Directory Traversal
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