Vulnerability · Published Sep 11, 2026 · Assigned by GitHub_M
CVE-2026-50018Hoverfly: Denial of Service via Goroutine Leak in Remote Post-Serve Actions
Medium 6.5
In plain English
A medium-severity uncontrolled resource consumption in hoverfly from SpectoLabs. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Hoverfly is an open source API simulation tool. Prior to version 1.12.8, remote post-serve actions use `http.DefaultClient` without any timeout configuration. When the remote endpoint is unreachable or intentionally slow (accepts TCP connection but never responds), each triggered proxy request spawns a goroutine that blocks indefinitely on `http.DefaultClient.Do()`. An attacker can cause unbounded goroutine accumulation leading to memory exhaustion and process crash (OOM kill). Unlike local post-serve action execution, this requires no binary execution, only a URL pointing to a non-responsive endpoint. Version 1.12.8 patches the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/SpectoLabs/hoverfly | 1.12.8 | GHSA-42j2-w334-qxw7 |
| Go | github.com/SpectoLabs/hoverfly | 1.12.8 | GO-2026-5975 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| SpectoLabs | hoverfly | < 1.12.8 |
Weakness: CWE-400, CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
References
- https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-42j2-w334-qxw7 x_refsource_CONFIRM
- https://github.com/SpectoLabs/hoverfly/pull/1228 x_refsource_MISC
- https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8 x_refsource_MISC