CVE-2026-42345: high-severity vulnerability in labring FastGPT
FastGPT: Cloud metadata endpoint SSRF protection bypass via port specification, IPv6 mapping, hex/decimal IP encoding, and trailing dot
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.7epss 0.2%
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:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Affected products
labring · FastGPTRelated CVEs — labring FastGPT
In the same product, most dangerous first.
CVE-2026-42302CRITICALFastGPT: Unauthenticated Remote Code Execution (RCE) via code-server Misconfiguration in agent-sandboxEPSS 0.7%CVE-2026-40351CRITICALFastGPT: NoSQL Injection in loginByPassword leads to Authentication BypassEPSS 0.6%CVE-2025-49131MEDIUMFastGPT Sandbox Vulnerable to Sandbox BypassEPSS 0.5%CVE-2026-55418HIGHFastGPT: S3 presign/read handlers do not bind the object key to the caller's team (cross-team file disclosure)EPSS 0.5%CVE-2026-68929CRITICALFastGPT: Unauthenticated WeChat channel hijack and denial of service via shareId-only authorizationEPSS 0.4%CVE-2026-34162CRITICALFastGPT: Unauthenticated SSRF via httpTools Endpoint Leads to Internal API Key TheftEPSS 0.4%