CVE intelligence and bounded remediation

CVE-2023-39967 — WireMock is a tool for mocking HTTP services

Critical CVSS 10

WireMock is a tool for mocking HTTP services. When certain request URLs like “@127.0.0.1:1234" are used in WireMock Studio configuration fields, the request might be forwarded to an arbitrary service reachable from WireMock’s instance. There are 3 identified potential attack vectors: via “TestRequester” functionality, webhooks and the proxy mode. As we can control HTTP Method, HTTP Headers, HTTP Data, it allows sending requests with the default level of credentials for the WireMock instance. The vendor has discontinued the affected Wiremock studio product and there will be no fix. Users are advised to find alternatives.

Severity
Critical
CVSS
10 (3.1)
Published
2023-09-06
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-918

Affected products

  • wiremock / studio

Matched remediation archetype

Server-side request forgery and unintended proxying

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Inventory server-side URL fetchers, webhooks, importers, previews, redirects, proxies, and protocol handlers reachable from untrusted input.
  • Map egress paths to internal services, metadata endpoints, loopback, private address space, and privileged control planes.
  • Review DNS resolution, redirect, proxy, credential-forwarding, and URL parsing behavior without requesting sensitive targets.

Remediate safely

  • Replace arbitrary destinations with named integrations or a strict allowlist of schemes, hosts, ports, and paths.
  • Resolve and validate every destination and redirect hop, then enforce egress policy independently of application checks.
  • Remove ambient credentials and sensitive headers from fetchers; apply response size, time, and content limits.

Authoritative sources

Complete CVE record and remediation plan

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