CVE-2026-30965: Parse Server Session Token Exfiltration Vulnerability
Summary
CVE-2026-30965: Parse Server vulnerable to session token exfiltration via redirectClassNameForKey query parameter. Affects parse-server across 2 version ranges.
< 8.6.21
>= 9.0.0-alpha.1, < 9.5.2-alpha.8
Fixed in 8.6.21 or 9.5.2-alpha.8, depending on the release line you run. How to fix ↓
Also tracked for
- parse · Bitnami
The same CVE-2026-30965 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Parse Server is an open-source backend platform that enables developers to build applications without managing their own server infrastructure. It provides a robust set of features including data storage, user authentication, and real-time notifications. However, it is susceptible to vulnerabilities that can compromise user data and session integrity, such as the one identified in CVE-2026-30965.
Vulnerability Detail
The vulnerability in Parse Server arises from improper handling of the redirectClassNameForKey query parameter, which allows both authenticated and unauthenticated attackers to exfiltrate session tokens belonging to other users. This can lead to unauthorized account access and potential data breaches. The issue is rooted in the server's query handling logic, which fails to enforce adequate security checks after a query redirect, exposing sensitive session information.
How To Fix
Latest published version: 9.10.5 as of 22 Oct 2026
npm install parse-server@9.10.5Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 8.6.218.6.21npm install parse-server@8.6.21 -
>= 9.0.0-alpha.1, < 9.5.2-alpha.89.5.2-alpha.8npm install parse-server@9.5.2-alpha.8
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Workaround
As a temporary measure, restrict Class-Level Permissions to prevent clients from creating new fields on classes. Specifically, disable the addField permission for public access and unauthenticated users. This can be done in the Parse Server dashboard or configuration settings.
Conclusion
CVE-2026-30965 represents a significant security risk for applications using Parse Server, allowing for session token exfiltration. It is crucial to update to the patched versions or implement the recommended workarounds to mitigate the risk of unauthorized access.
See every vulnerability recorded for parse-server →
FAQ
CVE-2026-30965 is a vulnerability in Parse Server that allows attackers to exfiltrate session tokens through the redirectClassNameForKey query parameter.
If exploited, attackers can gain unauthorized access to user accounts by obtaining session tokens, leading to potential data breaches.
Versions of Parse Server from 0.0.0 to 9.5.2-alpha.7 are affected by this vulnerability.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. Check your application against this vulnerability using the Vulert playground at Vulert Scanner.
The CVSS score for this vulnerability is 9.9, indicating a critical level of severity.
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