What’s Vulnerable › Vulnerabilities

CVE-2026-30229: Parse Server: Endpoint `/loginAs` allows `readOnlyMasterKey` to gain full read and write access as any user

• Severity: high (CVSS 7.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-06 · updated 2026-06-17
• Weakness: CWE-863

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.6 and 9.5.0-alpha.4, the readOnlyMasterKey can call POST /loginAs to obtain a valid session token for any user. This allows a read-only credential to impersonate arbitrary users with full read and write access to their data. Any Parse Server deployment that uses readOnlyMasterKey is affected. This issue has been patched in versions 8.6.6 and 9.5.0-alpha.4.

Affected products

• parse-community parse-server: before 8.6.6; from 9.0.0 through 9.4.1; 9.5.0-alpha1, 9.5.0-alpha2, 9.5.0-alpha3 — fixed in 8.6.6

How to fix

Upgrade to a fixed version: parse-community parse-server 8.6.6. Check the vendor advisory for mitigations.

References

• https://github.com/parse-community/parse-server/releases/tag/8.6.6
• https://github.com/parse-community/parse-server/releases/tag/9.5.0-alpha.4
• https://github.com/parse-community/parse-server/security/advisories/GHSA-79wj-8rqv-jvp5

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