Parse Server OAuth2 authentication adapter account takeover via identity spoofing

CVE-2026-30967 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-03-11 00:21:37 UTC
Updated
2026-03-11 00:21:39 UTC
GitHub reviewed
2026-03-11 00:21:37 UTC
NVD published
2026-03-10

EPSS Score

Score Percentile
0.11% 29.17%

CVSS Scores

Base score Version Severity Vector
7.6 4.0 —
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.

Identifiers

Type Value
GHSA GHSA-fr88-w35c-r596 ↗
CVE CVE-2026-30967 ↗

CWEs

CWE id Name
CWE-287 Improper Authentication

Credits

  • theinfosecguy (reporter)
  • mtrezza (coordinator)

Affected packages (2)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm parse-server >= 9.0.0-alpha.1, < 9.5.2-alpha.9 9.5.2-alpha.9 —
npm parse-server < 8.6.22 8.6.22 —

References

cvelogic Threat Intelligence