CVE-2026-40351

FastGPT: NoSQL Injection in loginByPassword leads to Authentication Bypass

Published Apr 17, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

Description

FastGPT is an AI Agent building platform. In versions prior to 4.14.9.5, the password-based login endpoint uses TypeScript type assertion without runtime validation, allowing an unauthenticated attacker to pass a MongoDB query operator object (e.g., {"$ne": ""}) as the password field. This NoSQL injection bypasses the password check, enabling login as any user including the root administrator. This issue has been fixed in version 4.14.9.5.

Analysis

Technical impact

FastGPT uses type assertions instead of runtime checks on the loginByPassword endpoint. An unauthenticated attacker can submit a MongoDB query operator object as the password, which the underlying database interprets and therefore bypasses the password check. This allows login as any user, including the root administrator, giving full control over the system without credentials.

Affected Systems

The FastGPT AI Agent building platform is affected in all releases prior to v4.14.9.5. Versions v4.14.9.5 and later contain the fix.

Risk and Exploitability

The CVSS score of 9.8 classifies this as a critical severity vulnerability. The EPSS score is not available, and the issue is not listed in the CISA KEV catalog. The vulnerability is exploitable through the publicly exposed login endpoint without needing any prior authentication. An attacker can simply construct a carefully crafted request to inject the query operator and obtain privileged access.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

labring

FastGPT

affected

Version	Status	Constraints
`< 4.14.9.5`	affected	—

Configuration 1 [-]

cpe:2.3:a:fastgpt:fastgpt:*:*:*:*:*:*:*:*

No data.

Vendor Product Versions

Labring

Fastgpt

Version	Status	Scheme	Platform
`[0,4.14.9.5)`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade FastGPT to version 4.14.9.5 or later, which includes the fix for the NoSQL injection flaw.
Restrict network access to the authentication endpoint, for example by using a firewall or VPN, to limit exposure to trusted hosts.
Implement strict server‑side validation of password inputs to reject any MongoDB query operators or non‑alphanumeric characters.

Generated by OpenCVE AI on April 18, 2026 at 08:56 UTC.

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.638% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact total

References

Link	Providers
https://github.com/labring/FastGPT/commit/bd966d479fbe414d02679cf79f9eaaab3d100a2d
https://github.com/labring/FastGPT/releases/tag/v4.14.9.5
https://github.com/labring/FastGPT/security/advisories/GHSA-x8mx-2mr7-h9xg

History

Apr 27, 2026 7:45 PM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Fastgpt Fastgpt fastgpt
CPEs		cpe:2.3:a:fastgpt:fastgpt::::::::
Vendors & Products		Fastgpt Fastgpt fastgpt

Apr 20, 2026 3:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Apr 17, 2026 10:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Labring Labring fastgpt
Vendors & Products		Labring Labring fastgpt

Apr 17, 2026 9:30 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		FastGPT is an AI Agent building platform. In versions prior to 4.14.9.5, the password-based login endpoint uses TypeScript type assertion without runtime validation, allowing an unauthenticated attacker to pass a MongoDB query operator object (e.g., {"$ne": ""}) as the password field. This NoSQL injection bypasses the password check, enabling login as any user including the root administrator. This issue has been fixed in version 4.14.9.5.
Title		FastGPT: NoSQL Injection in loginByPassword leads to Authentication Bypass
Weaknesses		CWE-943
References		https://github.com/labring/FastGPT/commit/bd966d479fbe414d02679cf79f9eaaab3d100a2d https://github.com/labring/FastGPT/releases/tag/v4.14.9.5 https://github.com/labring/FastGPT/security/advisories/GHSA-x8mx-2mr7-h9xg
Metrics		cvssV3_1 `{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}`