CVE-2026-50018: Hoverfly: Denial of Service via Goroutine Leak in Remote Post-Serve Actions
Vulnerability summary
CVE-2026-50018 is a medium (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in spectolabs hoverfly. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 45.6% of scored vulnerabilities.
Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 11-09-2026PublishedVulnerability first disclosed.
- 14-09-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · GoEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.54%
Chance of exploitation in the next 30 days
Percentile
46%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.54% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.
- CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Affected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Github.com/SpectoLabs1 product
- hoverfly< 1.12.8
Spectolabs1 product
- hoverfly< 1.12.8
2 vendors · 2 products
References
4 links- github.com/SpectoLabs/hoverfly/security/advisories/GHSA-42j2-w334-qxw7X Refsource CONFIRMWEBAdvisory