CVE-2026-42345
FastGPT: Cloud metadata endpoint SSRF protection bypass via port specification, IPv6 mapping, hex/decimal IP encoding, and trailing dot
Description
FastGPT is an AI Agent building platform. In versions 4.14.11 and prior, FastGPT's isInternalAddress() function in packages/service/common/system/utils.ts blocks cloud metadata endpoints using a fullUrl.startsWith() check against a hardcoded list. This check can be bypassed using at least 7 different URL encoding techniques, all of which resolve to the same cloud metadata service but do not match the blocklist patterns. Additionally, the broader private IP check (isInternalIPv4/isInternalIPv6) is disabled by default because CHECK_INTERNAL_IP defaults to false (not 'true'), so these bypasses reach the metadata endpoint without any further validation. At time of publication, there are no publicly available patches.
INFO
Published Date :
May 8, 2026, 11:16 p.m.
Last Modified :
July 24, 2026, 9:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Validate all external requests strictly.
- Enable and enforce internal IP address checks.
- Update the application to a patched version when available.
- Review and sanitize all URL inputs.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42345.
| URL | Resource |
|---|---|
| https://github.com/labring/FastGPT/security/advisories/GHSA-jhqw-944x-xh94 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42345 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42345
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42345 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42345 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: FastGPT de labring, Description: FastGPT es una plataforma de creación de agentes de IA. En las versiones 4.14.11 y anteriores, la función isInternalAddress() de FastGPT en packages/service/common/system/utils.ts bloquea los puntos finales de metadatos en la nube utilizando una comprobación fullUrl.startsWith() contra una lista codificada. Esta comprobación puede ser eludida utilizando al menos 7 técnicas diferentes de codificación de URL, todas las cuales se resuelven en el mismo servicio de metadatos en la nube pero no coinciden con los patrones de la lista de bloqueo. Además, la comprobación más amplia de IP privada (isInternalIPv4/isInternalIPv6) está deshabilitada por defecto porque CHECK_INTERNAL_IP por defecto es false (no 'true'), por lo que estas elusiones alcanzan el punto final de metadatos sin ninguna validación adicional. En el momento de la publicación, no hay parches disponibles públicamente. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'labring', 'product': 'FastGPT', 'versions': [{'status': 'affected', 'version': '<= 4.14.11'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-42345', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-13T17:20:45.691099Z'} -
New CVE Received by [email protected]
May. 08, 2026
Action Type Old Value New Value Added Description FastGPT is an AI Agent building platform. In versions 4.14.11 and prior, FastGPT's isInternalAddress() function in packages/service/common/system/utils.ts blocks cloud metadata endpoints using a fullUrl.startsWith() check against a hardcoded list. This check can be bypassed using at least 7 different URL encoding techniques, all of which resolve to the same cloud metadata service but do not match the blocklist patterns. Additionally, the broader private IP check (isInternalIPv4/isInternalIPv6) is disabled by default because CHECK_INTERNAL_IP defaults to false (not 'true'), so these bypasses reach the metadata endpoint without any further validation. At time of publication, there are no publicly available patches. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N Added CWE CWE-918 Added Reference https://github.com/labring/FastGPT/security/advisories/GHSA-jhqw-944x-xh94