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MEDIUM severity

Auth0 Symfony SDK has Improper Audience Validation via Auth0-PHP SDKGHSA-f3r2-88mq-9v4g

MEDIUMFix: auth0/symfony@0103d6f

GHSA-f3r2-88mq-9v4g is a medium-severity (CVSS 6.8) vulnerability in auth0/symfony. A fix is available for auth0/symfony — see the affected versions and patch details below.

Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Feb 4, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🐘auth0/symfony

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Description

In applications built with the Auth0-PHP SDK, the audience validation in access tokens is performed improperly. Without proper validation, affected applications may accept ID tokens as Access tokens.

Affected product and versions

Projects are affected if they meet the following preconditions:

  • Applications using the Auth0 Symfony SDK with versions between 5.0.0 and 5.5.0
  • Auth0 Symfony SDK uses the Auth0-PHP SDK with versions between 8.0.0 and 8.17.0.

Resolution

Upgrade Auth0/symfony to version 5.6.0 or greater.

Acknowledgement

Okta would like to thank Jafar Sadiq (iaf4r) for their discovery and responsible disclosure.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistauth0/symfony≥ 5.0.0&&< 5.6.05.6.0composer require auth0/symfony:^5.6.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for auth0/symfony, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update auth0/symfony to 5.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f3r2-88mq-9v4g is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Description In applications built with the Auth0-PHP SDK, the audience validation in access tokens is performed improperly. Without proper validation, affected applications may accept ID tokens as Access tokens. ### Affected product and versions Projects are affected if they meet the following preconditions: - Applications using the Auth0 Symfony SDK with versions between 5.0.0 and 5.5.0 - Auth0 Symfony SDK uses the Auth0-PHP SDK with versions between 8.0.0 and 8.17.0. ### Resolution Upgrade Auth0/symfony to version 5.6.0 or greater. ### Acknowledgement Okta would like to thank Jafar S
O3 Security · Impact-Aware SCA

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Auth0 Symfony SDK has Improper Audience Validation…