CVE-2026-42345 Server-side request forgery in FastGPT
Attackers can bypass SSRF protections in FastGPT to access cloud metadata endpoints via URL encoding tricks, potentially exposing sensitive credentials.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-42345?
CVE-2026-42345 is a high-severity server-side request forgery vulnerability in labring FastGPT, published on 8 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-918
Which versions are affected by CVE-2026-42345?
How do I fix CVE-2026-42345?
No fix has been published for CVE-2026-42345 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-42345 being exploited?
There is no known exploitation of CVE-2026-42345 in the wild and no public exploit code.
Sources
Also known as GHSA-jhqw-944x-xh94.