GHSA-9cp7-3q5w-j92g BIT-parse-2026-30835 CVE-2026-30835

parse-server: Malformed `$regex` query leaks database error details in API response

Medium npm

Severity: 0.0 / 10; Medium · CVSS 4.0
Exploit chance (EPSS): 0.35%; Chance of exploitation in the next 30 days. Higher than 28.56% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-209 Generation of Error Message Containing Sensitive Information
Fix: 9.5.0-alpha.6; Upgrade parse-server to this version or later

Description

Impact

A malformed $regex query parameter (e.g. [abc) causes the database to return a structured error object that is passed unsanitized through the API response. This leaks database internals such as error messages, error codes, code names, cluster timestamps, and topology details. The vulnerability is exploitable by any client that can send query requests, depending on the deployment's permission configuration.

Patches

The fix sanitizes database error objects so that only a generic "An internal server error occurred" message is returned to clients, while the detailed error is logged server-side. The fix respects the enableSanitizedErrorResponse server option.

Workarounds

There is no workaround other than upgrading. The error leakage occurs in the query execution layer and cannot be mitigated through server configuration or client-side changes.

Resources

GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-9cp7-3q5w-j92g
Fix in Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.0-alpha.6
Fix in Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.7

Affected versions

npm

Package	Vulnerable	Fixed in
parse-server	`>= 9.0.0, < 9.5.0-alpha.6`	`9.5.0-alpha.6`
parse-server	`< 8.6.7`	`8.6.7`

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 → `9.5.0-alpha.6`

npm

npm install parse-server@9.5.0-alpha.6

yarn

yarn add parse-server@9.5.0-alpha.6

pnpm

pnpm add parse-server@9.5.0-alpha.6

Severity breakdown

CVSS 4.0 0.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Attack vector: Network
Attack complexity: Low
Attack requirements: None
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-209: Generation of Error Message Containing Sensitive Information

The product generates an error message that includes sensitive information about its environment, users, or associated data.

How to prevent it

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.
Implementation: Handle exceptions internally and do not display errors containing potentially sensitive information to a user.
Implementation: Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.
Implementation, Build and Compilation: Debugging information should not make its way into a production release.
Implementation, Build and Compilation: Debugging information should not make its way into a production release.
System Configuration: Where available, configure the environment to use less verbose error messages. For example, in PHP, disable the display_errors setting during configuration, or at runtime using the error_reporting() function.
System Configuration: Create default error pages or messages that do not leak any information.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-30835

Packages

github.com/parse-community/parse-server

Timeline

Mar 6, 2026 Published
Jun 17, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

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

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