Critical severity · published Mar 24, 2026
CVE-2026-33409
Parse Server: Auth provider validation bypass on login via partial authData
9.1
CVSS
0.5%
EPSS
No
On KEV
Description
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.52 and 9.6.0-alpha.41, an authentication bypass vulnerability allows an attacker to log in as any user who has linked a third-party authentication provider, without knowing the user's credentials. The attacker only needs to know the user's provider ID to gain full access to their account, including a valid session token. This affects Parse Server deployments where the server option allowExpiredAuthDataToken is set to true. The default value is false. This issue has been patched in versions 8.6.52 and 9.6.0-alpha.41.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PA
parse-server · parse-community
< 8.6.52; >= 9.0.0, < 9.6.0-alpha.41 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33409
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33409
Patch
https://github.com/parse-community/parse-server/commit/8d7df5639c4a35768fe8b78b4580b30e8a74721c
Patch
https://github.com/parse-community/parse-server/commit/98f4ba5bcf2c199bfe6225f672e8edcd08ba732d
Issue Tracking
https://github.com/parse-community/parse-server/pull/10246
Issue Tracking
https://github.com/parse-community/parse-server/pull/10247
Vendor Advisory
https://github.com/parse-community/parse-server/security/advisories/GHSA-pfj7-wv7c-22pr
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