GHSA-w54v-hf9p-8856 BIT-parse-2026-31901 CVE-2026-31901
Parse Server vulnerable to user enumeration via email verification endpoint
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.25%
- Chance of exploitation in the next 30 days. Higher than 16.56% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-204 Observable Response Discrepancy
- Fix
9.6.0-alpha.8- Upgrade parse-server to this version or later
Description
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).
Patches
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.
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
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| parse-server | >= 9.0.0-alpha.1, < 9.6.0-alpha.8 |
9.6.0-alpha.8 |
| parse-server | < 8.6.34 |
8.6.34 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
parse-server npm → 9.6.0-alpha.8
- npm
npm install parse-server@9.6.0-alpha.8- yarn
yarn add parse-server@9.6.0-alpha.8- pnpm
pnpm add parse-server@9.6.0-alpha.8
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-204: Observable Response Discrepancy
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
How to prevent it
- Architecture and Design: Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
- Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-r899-h629-j84r Parse Server vulnerable to stored XSS via malformed Content-Type bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-97pr-9hgg-3p8r parse-server: LiveQuery discloses object data to a subscriber across an ACL read-access change | Low | Also affects parse-server |
| GHSA-v8x7-r927-cc93 parse-server: Stored XSS via non-standard file extension bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-cgxm-vr2f-6fj8 parse-server: Denial of service via exponential-time processing of deeply nested query operators | High | Also affects parse-server |
| GHSA-wmwx-jr2p-4j4r parse-server: Relation `$relatedTo` query bypasses `protectedFields` and owning-object ACL | Medium | Also affects parse-server |
| GHSA-75v4-m273-5j49 parse-server: Endpoints `/login` and `/verifyPassword` disclose MFA secrets and protected fields when `_User` get is denied | Medium | Also affects parse-server |
| GHSA-7wqv-xjf3-x35v parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-p84r-h6rx-f2xr parse-server: Server option routeAllowList is bypassable through batch sub-requests | Medium | Also affects parse-server |
MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.
Check your repos with MergeHarbor