New anonymous user session acts as if it's created with password
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-287.
Summary
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Developers can use the REST API to signup users and also allow users to login anonymously. Prior to version 4.5.1, when an anonymous user is first signed up using REST, the server creates session incorrectly. Particularly, the `authProvider` field in `_Session` class under `createdWith` shows the user logged in creating a password. If a developer later depends on the `createdWith` field to provide a different level of access between a password user and anonymous user, the server incorrectly classified the session type as being created with a `password`. The server does not currently use `createdWith` to make decisions about internal functions, so if a developer is not using `createdWith` directly, they are not affected. The vulnerability only affects users who depend on `createdWith` by using it directly. The issue is patched in Parse Server version 4.5.1. As a workaround, do not use the `createdWith` Session field to make decisions if one allows anonymous login.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| parse-community | parse-server | before 4.5.1 | 4.5.1 | Patch available | CNA |
| — | parse-server (npm) | before 4.5.2 | 4.5.2 | Patch available | GHSA-23r4-5mxp-c7g5 |
- parse-server Vendorparse-community Affected before 4.5.1 Fixed in 4.5.1 Patch available CNA
- parse-server (npm) Vendor— Affected before 4.5.2 Fixed in 4.5.2 Patch available GHSA-23r4-5mxp-c7g5
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:parseplatform:parse-server:*:*:*:*:*:node.js:*:* | before 4.5.1 | Vulnerable | parse-community |
- cpe:2.3:a:parseplatform:parse-server:*:*:*:*:*:node.js:*:* Versions before 4.5.1 Vulnerable ·parse-community
Remediation
- Fix · CNA parse-server (parse-community) Fixed in 4.5.1
- Fix · GHSA-23r4-5mxp-c7g5 parse-server (npm) Fixed in 4.5.2 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2021-39138
- 2026-10-03 Alias added: GHSA-23r4-5mxp-c7g5
References
Patch 1
Advisory 3
More parse-community Parse-server vulnerabilities
- TI-2022-08574 Command Injection in Parse server CVSS 3.1CRITICAL 10.0
- TI-2024-18136 Parse Server literalizeRegexPart SQL Injection CVSS 3.1CRITICAL 10.0
- TI-2022-18768 Parse Server vulnerable to Remote Code Execution via prototype pollution in MongoDB BSON parser CVSS 3.1CRITICAL 9.8
- TI-2024-31550 Parse Server's custom object ID allows to acquire role privileges CVSS 3.1HIGH 8.1
- TI-2023-18316 Parse Server vulnerable to remote code execution via MongoDB BSON parser through prototype pollution CVSS 3.1CRITICAL 9.8
- TI-2026-23790 Parse Server session token exfiltration via `redirectClassNameForKey` query parameter CVSS 4.0CRITICAL 9.9
Sources
- CVE-2021-39138 · CVE Program
- CVE-2021-39138 · NVD
- FIRST EPSS
- GHSA-23r4-5mxp-c7g5 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences