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 is vulnerable to DNS rebinding (TOCTOU — Time-of-Check to Time-of-Use). The function resolves the hostname via dns.resolve4()/dns.resolve6() and checks resolved IPs against private ranges, but the actual HTTP request happens in a separate call with a new DNS resolution, allowing the DNS record to change between validation and fetch. At time of publication, there are no publicly available patches.
### Summary
Authenticated Server-Side Request Forgery affecting the webhook trigger tools, the n8n API client (`N8N_API_URL`), and per-request URLs supplied via the `x-n8n-url` header in multi-tenant HTTP mode.
### Impact
A caller with access to the MCP session can drive HTTP requests from the n8n-mcp host to internal services and cloud metadata endpoints that the SSRF gate is meant to block. The response body is returned to the caller, making internal-service enumeration and credential theft immediate without any out-of-band channel.
- **Multi-tenant HTTP deployments** where tenants share an `AUTH_TOKEN`: any tenant with valid credentials can reach the operator's cloud metadata service and exfiltrate temporary IAM / GCP service account / Azure managed-identity credentials.
- **Single-tenant deployments**: indirect prompt injection through tool arguments reaches the same surface; an attacker who can influence the LLM's tool calls can read internal services from the n8n-mcp host.
- **Stdio deployments** are reachable via the same prompt-injection path.
### Patched Versions
Fixed in `n8n-mcp@2.50.2`.
**Note for operators:** The same SSRF gate that previously covered webhook URLs now also covers the n8n API client base URL. If `N8N_API_URL` points at `http://localhost:5678` (n8n on the same host) or an RFC1918 address (n8n on the same private network), set `WEBHOOK_SECURITY_MODE=moderate` (allows localhost, still blocks RFC1918 and cloud metadata) or `WEBHOOK_SECURITY_MODE=permissive` (allows RFC1918 too — only safe on a trusted private network). Default `strict` is correct for deployments where n8n is reachable at a public hostname.
### Workarounds
For deployments that cannot upgrade immediately:
1. **Restrict network egress** from the n8n-mcp host with a firewall, reverse proxy, or cloud security group. Explicitly deny cloud metadata IPs (`169.254.169.254`, `169.254.170.2`, `100.100.100.200`, `192.0.0.192`, and the GCP `metadata.google.internal` resolved IP) and any RFC1918 networks the server does not legitimately need to reach.
2. **Run in stdio mode** instead of HTTP if the multi-tenant surface is not needed (no shared `AUTH_TOKEN` to compromise).
3. **Disable workflow management tools** via `DISABLED_TOOLS=n8n_trigger_webhook_workflow,n8n_create_workflow,n8n_test_workflow` if the deployment does not need them.
### Credit
Reported by [@fg0x0](https://github.com/fg0x0).
Due to multiple time-of-check time-of-use race conditions in the resource count check and increment logic, as well as missing validations, users of the platform are able to exceed the allocation limits configured for their accounts/domains. This can be used by an attacker to degrade the infrastructure's resources and lead to denial of service conditions.
Users are recommended to upgrade to Apache CloudStack versions 4.20.3.0 or 4.22.0.1, or later, which fixes this issue.
Akamai Guardicore Platform Agent (GPA) and Zero Trust Client on Linux and macOS allow TOCTOU-based local privilege escalation. The GPA service creates an IPC socket in the world-writable /tmp directory. It accepts unauthenticated IPC control messages. This enables a TOCTOU vulnerability in the HandleSaveLogs() function of the GPA service, by creating a log file and manipulating it into a symlink that points to the targeted path; this can allow an unprivileged local user to make arbitrary root-owned files world-writable. In addition, a diagnostic collection tool (gimmelogs) running with root privileges was vulnerable to command injection from the dbstore, offering a second privilege escalation vector. (On Windows, gimmelogs does not have command injection but does allow writing a ZIP archive to an unintended location.) This affects Akamai Guardicore Platform Agent 7.0 through 7.3.1 and Akamai Zero Trust Client 6.0 through 6.1.5.
The base directory (`spring.cloud.config.server.git.basedir`) used by the Spring Cloud Config Server to clone Git repositories to is susceptible to time-of-check-time-of-use (TOCTOU) attacks.
Spring Cloud Config 3.1.x: affected from 3.1.0 through 3.1.13 (inclusive); upgrade to 3.1.14 or greater (Enterprise Support Only). Spring Cloud Config 4.1.x: affected from 4.1.0 through 4.1.9 (inclusive); upgrade to 4.1.10 or greater (Enterprise Support Only). Spring Cloud Config 4.2.x: affected from 4.2.0 through 4.2.6 (inclusive); upgrade to 4.2.7 or greater (Enterprise Support Only). Spring Cloud Config 4.3.x: affected from 4.3.0 through 4.3.2 (inclusive); upgrade to 4.3.3 or greater. Spring Cloud Config 5.0.x: affected from 5.0.0 through 5.0.2 (inclusive); upgrade to 5.0.3 or greater.
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