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GHSA-fr88-w35c-r596

HighCVSS 7.6 / 10

Published Mar 11, 2026·Last modified Mar 14, 2026

Affected Components(0)

No affected components available

Description

Impact

The OAuth2 authentication adapter, when configured without the useridField option, only verifies that a token is active via the provider's token introspection endpoint, but does not verify that the token belongs to the user identified by authData.id. An attacker with any valid OAuth2 token from the same provider can authenticate as any other user.

This affects any Parse Server deployment that uses the generic OAuth2 authentication adapter (configured with oauth2: true) without setting the useridField option.

Patches

The vulnerability is fixed by defaulting useridField to sub, which is the standard subject identifier field defined by RFC 7662. The adapter now always validates the token's identity against the claimed user ID, even when useridField is not explicitly configured.

Workarounds

Set the useridField option to the appropriate field name for your OAuth2 provider (e.g. sub) in the Parse Server authentication configuration.

References

GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-fr88-w35c-r596
Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.9
Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.22

Risk Scores

Base Score

7.6

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence

4.9

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS

0.33%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit

Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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