High severity · published May 8, 2026
CVE-2026-42345
FastGPT: Cloud metadata endpoint SSRF protection bypass via port specification, IPv6 mapping, hex/decimal IP encoding, and trailing dot
7.7
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FA
FastGPT · labring
<= 4.14.11 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42345
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42345
github.com
https://github.com/labring/FastGPT/security/advisories/GHSA-jhqw-944x-xh94
More from FastGPT
10.0
CVE-2026-34162
FastGPT: Unauthenticated SSRF via httpTools Endpoint Leads to Internal API Key Theft
9.9
CVE-2025-49131
FastGPT Sandbox Vulnerable to Sandbox Bypass
9.8
CVE-2026-42302
FastGPT: Unauthenticated Remote Code Execution (RCE) via code-server Misconfiguration in agent-sandbox
9.8
CVE-2026-40351
FastGPT: NoSQL Injection in loginByPassword leads to Authentication Bypass
9.3
CVE-2026-68929
FastGPT: Unauthenticated WeChat channel hijack and denial of service via shareId-only authorization
