CVE-2026-33429: Parse Server: Protected field change detection oracle via LiveQuery watch parameter
Impact
An attacker can subscribe to LiveQuery with a watch parameter targeting a protected field. Although the protected field value is properly stripped from event payloads, the presence or absence of update events reveals whether the protected field changed, creating a binary oracle. For boolean protected fields, the timing of change events is equivalent to knowing the field value.
Patches
The watch parameter is now validated against protected fields at subscription time, mirroring the existing validation for the where clause. Subscriptions that include protected fields in watch are rejected with a permission error. Master key connections are exempt.
Workarounds
None.
Other sources
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.54 and 9.6.0-alpha.43, an attacker can subscribe to LiveQuery with a watch parameter targeting a protected field. Although the protected field value is properly stripped from event payloads, the presence or absence of update events reveals whether the protected field changed, creating a binary oracle. For boolean protected fields, the timing of change events is equivalent to knowing the field value. This issue has been patched in versions 8.6.54 and 9.6.0-alpha.43.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33429?
CVE-2026-33429 is classified as a moderate severity vulnerability.
How do I fix CVE-2026-33429?
To fix CVE-2026-33429, upgrade Parse Server to version 8.6.54 or 9.6.0-alpha.43 or later.
What type of attack can CVE-2026-33429 facilitate?
CVE-2026-33429 can facilitate an attacker’s ability to determine changes in protected field values through LiveQuery.
Who is affected by CVE-2026-33429?
CVE-2026-33429 affects users of Parse Server versions prior to 8.6.54 and specific alpha versions up to 9.6.0-alpha.43.
What is the impact of CVE-2026-33429?
The impact of CVE-2026-33429 includes potential exposure of sensitive information via event payloads in LiveQuery.