Summary
Workarounds
There is no known workaround.
References
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-w54v-hf9p-8856
- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.8
- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.34
Impact
The email verification endpoint (/verificationEmailRequest) returns distinct error responses depending on whether an email address belongs to an existing user, is already verified, or does not exist. An attacker can send requests with different email addresses and observe the error codes to determine which email addresses are registered in the application.
This is a user enumeration vulnerability that affects any Parse Server deployment with email verification enabled (verifyUserEmails: true).
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
The fix introduces a new Parse Server option emailVerifySuccessOnInvalidEmail (default: true) that returns a generic success response for all verification email requests, regardless of whether the email address is valid, already verified, or non-existent. This prevents an attacker from distinguishing between these cases.
The fix also strengthens the input validation for the related resetPasswordSuccessOnInvalidEmail option, and adds security checks that warn when either enumeration mitigation is disabled.
Frequently Asked Questions
- What is CVE-2026-31901? CVE-2026-31901 is a medium-severity security vulnerability in parse-server (npm), affecting versions >= 9.0.0-alpha.1, < 9.6.0-alpha.8. It is fixed in 9.6.0-alpha.8, 8.6.34.
- Which versions of parse-server are affected by CVE-2026-31901? parse-server (npm) versions >= 9.0.0-alpha.1, < 9.6.0-alpha.8 is affected.
- Is there a fix for CVE-2026-31901? Yes. CVE-2026-31901 is fixed in 9.6.0-alpha.8, 8.6.34. Upgrade to this version or later.
- Is CVE-2026-31901 exploitable, and should I be worried? Whether CVE-2026-31901 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-31901 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-31901?
- Upgrade
parse-serverto 9.6.0-alpha.8 or later - Upgrade
parse-serverto 8.6.34 or later
- Upgrade