CVE-2026-33527: Parse Server: Session update endpoint allows overwriting server-generated session fields
Impact
An authenticated user can overwrite server-generated session fields such as expiresAt and createdWith when updating their own session via the REST API. This allows bypassing the server's configured session lifetime policy, making a session effectively permanent.
Patches
The fix blocks authenticated users from setting expiresAt and createdWith fields when updating a session. Master key and maintenance key operations are not affected.
Workarounds
There is no known workaround other than upgrading.
Resources
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-jc39-686j-wp6q - Fix Parse Server 9: https://github.com/parse-community/parse-server/pull/10263 - Fix Parse Server 8: https://github.com/parse-community/parse-server/pull/10264
Other sources
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.57 and 9.6.0-alpha.48, an authenticated user can overwrite server-generated session fields such as expiresAt and createdWith when updating their own session via the REST API. This allows bypassing the server's configured session lifetime policy, making a session effectively permanent. This issue has been patched in versions 8.6.57 and 9.6.0-alpha.48.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33527?
CVE-2026-33527 is considered a medium severity vulnerability due to the potential for an authenticated user to manipulate session data.
How do I fix CVE-2026-33527?
To fix CVE-2026-33527, upgrade to version 9.6.0-alpha.48 or 8.6.57 of 'parse-server'.
Who is affected by CVE-2026-33527?
CVE-2026-33527 affects all authenticated users of 'parse-server' versions prior to 8.6.57 and between 9.0.0 to 9.6.0-alpha.48.
What components are involved in CVE-2026-33527?
CVE-2026-33527 involves the session update endpoint of the Parse Server's REST API.
How can CVE-2026-33527 be exploited?
CVE-2026-33527 can be exploited by an authenticated user who sends a request to overwrite server-generated session fields.