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VulnerabilityPublished 07/24/2026

Adapters: FrontMCP: Server-Side Request Forgery (SSRF) in the OpenAPI adapter spec-change poller

Affects @frontmcp/adaptersSource GCVE Database

0

CVSS 5.9 Medium · fixed in 1.5.6 : update @frontmcp/adapters when convenient.

Data as of 07/25/2026, 23:48:32 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 1.5.6
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

What to do

Affected software

ProductAffectedFixed in
npm@frontmcp/adaptersAffected
  • <1.5.6
Fixed in
  • 1.5.6

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AI-suggested

A fix is available in @frontmcp/adapters version 1.5.6 and later. The patch routes the poller's fetch through the same SSRF guard as the initial spec load, enforcing allow/block lists, IP blocking, DNS pinning, and redirect validation. Users should upgrade to version 1.5.6 or later to remediate this vulnerability. If upgrading is not immediately possible, disabling polling or ensuring the spec URL is fixed and fully trusted can mitigate risk. Patch status is confirmed by the vendor advisory. No additional mitigation is required once patched.

Description

The OpenAPI adapter in @frontmcp/adapters versions prior to 1.5.6 contains a Server-Side Request Forgery (SSRF) vulnerability in its spec-change poller. While the initial spec load is protected by an SSRF guard, the recurring poller fetches the spec URL using an unguarded global fetch, bypassing protections such as allow-list/block-list enforcement, internal IP blocking, DNS resolution pinning, and redirect validation. This allows an attacker who can influence the spec URL to cause the server to make unauthorized GET requests to internal or otherwise protected network resources. The vulnerability primarily impacts confidentiality by enabling reading of internal endpoints, including cloud metadata services. The issue is fixed in version 1.5.6 by routing the poller's fetch through the same SSRF guard as the initial load.

Impact

Exploitation requires polling enabled and an untrusted or attacker-controllable spec URL. The server will make repeated unguarded GET requests to the specified URL, which can resolve to internal or private network addresses. This can lead to unauthorized access to internal services, cloud metadata endpoints (e.g., 169.254.169.254), and internal network scanning. The primary impact is confidentiality loss due to unauthorized reading of internal resources. Integrity and availability impacts are not indicated. The vulnerability does not affect servers polling fixed, trusted spec URLs in practice but represents a risk if the URL is attacker-influenceable.

Weaknesses

References

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