CVE-2026-33527: Parse Server Session Update Vulnerability Allows Session Field Overwrite
Summary
CVE-2026-33527: Parse Server's Session Update endpoint allows overwriting server-generated session fields. Affects parse-server across 2 version ranges.
< 8.6.57
>= 9.0.0, < 9.6.0-alpha.48
Fixed in 8.6.57 or 9.6.0-alpha.48, depending on the release line you run. How to fix ↓
Also tracked for
- parse · Bitnami
The same CVE-2026-33527 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 framework that enables developers to build applications with a robust and scalable server infrastructure. It provides features such as data storage, user authentication, and real-time notifications. However, a vulnerability has been identified in its Session Update endpoint, which allows authenticated users to overwrite critical server-generated session fields.
Vulnerability Detail
The vulnerability arises from the ability of authenticated users to modify server-generated session fields like 'expiresAt' and 'createdWith' through the REST API. This can lead to a situation where users can bypass the configured session lifetime policy, effectively making their sessions permanent. The issue is categorized under CWE-863, indicating a problem with the authorization of actions.
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.
-
< 8.6.578.6.57npm install parse-server@8.6.57 -
>= 9.0.0, < 9.6.0-alpha.489.6.0-alpha.48npm install parse-server@9.6.0-alpha.48
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Workaround
There is no known workaround other than upgrading to the patched version of Parse Server.
Conclusion
In summary, CVE-2026-33527 is a vulnerability in Parse Server that allows authenticated users to overwrite critical session fields, potentially leading to permanent sessions. It is essential to upgrade to the patched versions to ensure the security of your application.
See every vulnerability recorded for parse-server →
FAQ
An authenticated user can overwrite session fields, potentially making their session permanent and bypassing session lifetime policies.
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Versions 0 to 9.6.0-alpha.48 of Parse Server are affected by this vulnerability.
The CVSS score of this vulnerability is 5.3, indicating a moderate severity level.
While there are no workarounds available, it is crucial to prioritize upgrading to the patched version as soon as possible to mitigate the risk.
References
Related vulnerabilities
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