CVE-2026-33323: Parse Server: Email verification resend page leaks user existence
Impact
The Pages route and legacy PublicAPI route for resending email verification links return distinguishable responses depending on whether the provided username exists and has an unverified email. This allows an unauthenticated attacker to enumerate valid usernames by observing different redirect targets. The existing emailVerifySuccessOnInvalidEmail configuration option, which is enabled by default and protects the API route against this, did not apply to these routes.
Patches
The email verification resend routes now respect the emailVerifySuccessOnInvalidEmail option. When set to true (the default), both routes redirect to the success page regardless of the outcome, preventing user enumeration.
Workarounds
There is no known workaround to prevent the information disclosure other than upgrading.
Other sources
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.51 and 9.6.0-alpha.40, the Pages route and legacy PublicAPI route for resending email verification links return distinguishable responses depending on whether the provided username exists and has an unverified email. This allows an unauthenticated attacker to enumerate valid usernames by observing different redirect targets. The existing emailVerifySuccessOnInvalidEmail configuration option, which is enabled by default and protects the API route against this, did not apply to these routes. This issue has been patched in versions 8.6.51 and 9.6.0-alpha.40.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33323?
CVE-2026-33323 is classified as a medium severity vulnerability primarily due to its potential for user enumeration.
How do I fix CVE-2026-33323?
To remediate CVE-2026-33323, upgrade to version 8.6.51 or 9.6.0-alpha.40 of the parse-server package.
What types of software are affected by CVE-2026-33323?
CVE-2026-33323 affects parse-server versions before 8.6.51 and versions between 9.0.0 and 9.6.0-alpha.40.
Can CVE-2026-33323 be exploited by unauthenticated users?
Yes, CVE-2026-33323 can be exploited by unauthenticated attackers to enumerate valid usernames.
What is the main issue caused by CVE-2026-33323?
The main issue with CVE-2026-33323 is that it allows attackers to determine whether a username exists based on response variations.