vulnerability / NVI-00015388 / Revision 1
FrontMCP: Server-Side Request Forgery (SSRF) in the OpenAPI adapter spec-change poller
GitHub lists this reviewed advisory for @frontmcp/adapters. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.9 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
@frontmcp/adapters
source listed<= 1.5.5
## Summary The OpenAPI adapter's spec-change **poller** (`OpenApiSpecPoller`) re-fetched the configured spec `url` on a timer using a raw global `fetch()`, bypassing the SSRF guard (`safeFetch` / `assertUrlSafe`) that `OpenAPIToolGenerator.fromURL()` applies to the initial spec load. As a result, the pinning/DNS-resolution hardening delivered via `mcp-from-openapi >= 2.5.0` (advisory GHSA-65h7-9wrw-629c) protected the initial load but **not** the recurring poll of the same URL. When polling is enabled against an untrusted or attacker-influenceable spec URL, this is an unguarded SSRF vector. ## Details The initial spec load is guarded. `OpenapiAdapter` resolves a secure `refResolution` policy and passes it to the guarded loader: ```ts // libs/adapters/src/openapi/openapi.adapter.ts — initializeGenerator() return await OpenAPIToolGenerator.fromURL(this.options.url, { // ... followRedirects: this.options.loadOptions?.followRedirects ?? false, refResolution, // secure default: external $refs off, internal targets blocked }); ``` But the poller — which re-fetches **the same URL** on every interval — did not: ```ts // libs/adapters/src/openapi/openapi-spec-poller.ts — doFetch
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-8q49-2h5h-434x ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.