GHSA-g4cf-xj29-wqqr BIT-parse-2026-33538 CVE-2026-33538

Parse Server: Denial of Service via unindexed database query for unconfigured auth providers

High npm

Severity: 0.0 / 10; High · CVSS 4.0
Exploit chance (EPSS): 0.42%; Chance of exploitation in the next 30 days. Higher than 36.53% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-400 Uncontrolled Resource Consumption
Fix: 9.6.0-alpha.52; Upgrade parse-server to this version or later

Description

Impact

An unauthenticated attacker can cause Denial of Service by sending authentication requests with arbitrary, unconfigured provider names. The server executes a database query for each unconfigured provider before rejecting the request, and since no database index exists for unconfigured providers, each request triggers a full collection scan on the user database. This can be parallelized to saturate database resources.

Patches

The fix validates that an authentication provider is configured before executing any database query. Requests with unconfigured providers are now rejected immediately without querying the database.

Workarounds

There is no known workaround other than upgrading.

Affected versions

npm

Package	Vulnerable	Fixed in
parse-server	`>= 9.0.0, < 9.6.0-alpha.52`	`9.6.0-alpha.52`
parse-server	`< 8.6.58`	`8.6.58`

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.52`

npm

npm install parse-server@9.6.0-alpha.52

yarn

yarn add parse-server@9.6.0-alpha.52

pnpm

pnpm add parse-server@9.6.0-alpha.52

Severity breakdown

CVSS 4.0 0.0

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

Attack vector: Network
Attack complexity: Low
Attack requirements: None
Privileges required: None
User interaction: None
Confidentiality (vulnerable system): None
Integrity (vulnerable system): None
Availability (vulnerable system): High
Confidentiality (subsequent systems): None
Integrity (subsequent systems): None
Availability (subsequent systems): None

CVSS 3.1 7.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Weakness

CWE-400: Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

How to prevent it

Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
Implementation: Ensure that all failures in resource allocation place the system into a safe posture.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-33538

Packages

github.com/parse-community/parse-server

Timeline

Mar 24, 2026 Published
Jun 17, 2026 Last updated by the source
Nov 1, 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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