CVE-2026-109303: Parse Server Protected Fields Bypass Vulnerability
Summary
CVE-2026-109303: Parse Server before 8.6.93 and 9.0.0 before 9.10.1 protectedFields Bypass via Relation Count Query. Affects parse across 2 version ranges.
< 8.6.93
>= 9.0.0, < 9.10.1
Fixed in 8.6.93 or 9.10.1, depending on the release line you run. How to fix ↓
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Background
Parse Server is an open-source backend platform that provides a robust framework for building applications. It offers features such as data storage, user authentication, and real-time notifications. However, certain versions of Parse Server are vulnerable to a bypass of protected fields, which can expose sensitive information to authenticated users.
Vulnerability Detail
The vulnerability arises in Parse Server versions prior to 8.6.93 and 9.0.0 before 9.10.1, where the enforcement of identity-scoped protected fields is not applied on count queries using the $relatedTo operator. This oversight allows authenticated users to exploit the system by combining count queries with objectId constraints, thereby revealing confidential memberships such as private groups or block lists. The potential ramifications include unauthorized access to sensitive data, which could lead to privacy breaches and data leaks.
How To Fix
Fixed versions by release line
The minimum fixed version depends on the release line you run.
-
< 8.6.938.6.93 -
>= 9.0.0, < 9.10.19.10.1
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
As a temporary workaround, consider restricting access to sensitive data by implementing additional checks in your application logic to prevent unauthorized users from executing count queries on protected fields.
Conclusion
CVE-2026-109303 represents a significant security risk for users of Parse Server versions prior to the patched releases. It is crucial to update to the latest versions to safeguard sensitive data and maintain the integrity of your applications.
See every vulnerability recorded for parse →
FAQ
CVE-2026-109303 is a vulnerability in Parse Server that allows authenticated users to bypass protections on sensitive data through count queries.
Parse Server versions before 8.6.93 and 9.0.0 before 9.10.1 are affected by this vulnerability.
The risks include unauthorized access to confidential memberships and potential privacy breaches.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
If an immediate update is not possible, implement additional access controls in your application to mitigate the risk of unauthorized data exposure.
References
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