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GHSA-5fw2-8jcv-xh87

CriticalCVSS 9.3 / 10
Published Mar 12, 2026·Last modified Mar 16, 2026
Affected Components(0)

No affected components available

Description

Impact

An unauthenticated attacker can take over any user account that was created with an authentication provider that does not validate the format of the user identifier (e.g. anonymous authentication). By sending a crafted login request, the attacker can cause the server to perform a pattern-matching query instead of an exact-match lookup, allowing the attacker to match an existing user and obtain a valid session token for that user's account. Both MongoDB and PostgreSQL database backends are affected. Any Parse Server deployment that allows anonymous authentication (enabled by default) is vulnerable.

Patches

The fix enforces that the user identifier in authentication data is a string before using it in a database query. Non-string values are rejected with a validation error.

Workarounds

There is no known workaround.

References

  • GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-5fw2-8jcv-xh87
  • Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.12
  • Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.38
Risk Scores
Base Score
9.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
8.0

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.63%

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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