GHSA-hq8w-9w8w-pmx7
MEDIUMWireMock Controlled Server Side Request Forgery vulnerability through URL
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
org.wiremock:wiremock-webhooks-extension☕org.wiremock:wiremock-webhooks-extensionReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Impact
WireMock can be configured to only permit proxying (and therefore recording) to certain addresses. This is achieved via a list of allowed address rules and a list of denied address rules, where the allowed list is evaluated first. Documentation.
Until WireMock Webhooks Extension 3.0.0-beta-15, the filtering of target addresses from the proxy mode DID NOT work for Webhooks, so the users were potentially vulnerable regardless of the limitProxyTargets settings.
Via the WireMock webhooks configuration, POST requests from a webhook might be forwarded to an arbitrary service reachable from WireMock’s instance. For example, If someone is running the WireMock docker Container inside a private cluster, they can trigger internal POST requests against unsecured APIs or even against secure ones by passing a token, discovered using another exploit, via authentication headers.
Affected components
- WireMock Webhooks Extension 2.x versions until 2.35.1 (security patch)
- WireMock 3.x version until 3.0.3 (security patch)
- All versions of WireMock Studio (discontinued). This distribution bundles the WireMock Webhooks Extension and activates it by default
Patches and Mitigation
- For WireMock 2.x and 3.x - upgrade to the versions with the security patches
- Setup network restrictions similarly to https://wiremock.org/docs/configuration/#preventing-proxying-to-and-recording-from-specific-target-addresses
- For WireMock Studio: Stop using discontinued WireMock Studio, migrate to other distributions. The vendor of WireMock Studio recommends migration to WireMock Cloud
NOTE: It was confirmed that WireMock Cloud does not expose sensitive internal APIs and hence not vulnerable to the issue. No action is needed if you use this SaaS distribution.
Workarounds
- Use external firewall rules to define the list of permitted destinations
References
Credits
- @W0rty for reporting CVE-2023-39967 in WireMock Studio
- WireMock Inc. team for discovering similar exploits in Webhooks and the risk in the Proxy mode defaults for WireMock
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.wiremock:wiremock-webhooks-extension | ≥ 3.0.0&&< 3.0.3 | 3.0.3 |
| ☕Maven | org.wiremock:wiremock-webhooks-extension | ≥ 2.0.0&&< 2.35.1 | 2.35.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.wiremock:wiremock-webhooks-extension. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.wiremock:wiremock-webhooks-extension to 3.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hq8w-9w8w-pmx7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-hq8w-9w8w-pmx7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-hq8w-9w8w-pmx7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-hq8w-9w8w-pmx7 in your dependencies?
O3 detects GHSA-hq8w-9w8w-pmx7 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.