CVE-2026-33508: Parse Server LiveQuery Subscription Query Depth Bypass Vulnerability
Summary
CVE-2026-33508: Parse Server LiveQuery subscription query depth bypass. Affects parse-server across 2 version ranges.
< 8.6.56
>= 9.0.0, < 9.6.0-alpha.45
Fixed in 8.6.56 or 9.6.0-alpha.45, depending on the release line you run. How to fix ↓
Also tracked for
- parse · Bitnami
The same CVE-2026-33508 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Habilume
Habit tracker with a companion that grows with you
Complete habits, earn Lume Points, and watch your Lume grow as you stay consistent.
Background
Parse Server is an open-source backend platform that enables developers to build applications with a robust server-side infrastructure. It provides features such as data storage, user authentication, and real-time capabilities through LiveQuery. However, the LiveQuery component has a vulnerability that allows attackers to exploit deeply nested logical operators in subscription queries, potentially leading to service degradation.
Vulnerability Detail
The vulnerability arises from the LiveQuery component of Parse Server not enforcing the 'requestComplexity.queryDepth' configuration setting for WebSocket subscription requests. This oversight allows attackers to send subscriptions with excessive query depth, resulting in high CPU consumption and service disruption. The issue is particularly critical when the LiveQuery WebSocket endpoint is accessible to untrusted clients, leading to potential denial-of-service conditions.
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.
-
< 8.6.568.6.56npm install parse-server@8.6.56 -
>= 9.0.0, < 9.6.0-alpha.459.6.0-alpha.45npm install parse-server@9.6.0-alpha.45
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
Currently, there are no known workarounds other than upgrading to the patched versions mentioned above.
Conclusion
The CVE-2026-33508 vulnerability in Parse Server's LiveQuery component poses a significant risk due to its potential for service disruption. Users are strongly advised to upgrade to the latest patched versions to mitigate this risk effectively.
See every vulnerability recorded for parse-server →
FAQ
The CVSS score of this vulnerability is 8.2, indicating a high severity level.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The potential impacts include excessive CPU consumption and service degradation, which can lead to denial-of-service conditions.
Currently, there are no known workarounds other than upgrading to the patched versions.
If immediate upgrading is not possible, consider restricting access to the LiveQuery WebSocket endpoint to trusted clients only.
References
Related vulnerabilities
Recent vulnerabilities recorded for parse-server.
Habilume
Habit tracker with a companion that grows with you
Complete habits, earn Lume Points, and watch your Lume grow as you stay consistent.
