Is CVE-2026-50013 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-50013 being exploited in the wild.

How severe is CVE-2026-50013?

High severity, with a CVSS score of 7.5, published 11 September 2026.

Which products and versions are affected?

github.com/SpectoLabs/hoverfly (Go) <= 1.12.7, SEMVER:introduced=0,fixed=1.12.8; SpectoLabs Hoverfly <= 1.12.7.

Is there a fix for CVE-2026-50013?

Yes. github.com/SpectoLabs/hoverfly (Go): upgrade to 1.12.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-50013 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-50013?

Check whether you run github.com/SpectoLabs/hoverfly (Go) or SpectoLabs Hoverfly at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-50013: SpectoLabs Hoverfly race condition in Diff mode

Q: Is there a fix for CVE-2026-50013?

Yes. github.com/SpectoLabs/hoverfly (Go): upgrade to 1.12.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-50013 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-50013?

Check whether you run github.com/SpectoLabs/hoverfly (Go) or SpectoLabs Hoverfly at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-50013 · Severity: high · CVSS 7.5 · Published 2026-09-11

Hoverfly is an API simulation tool used for development and testing. A flaw in its 'Diff' mode allows an attacker to crash the service by sending multiple simultaneous requests. This results in a total service outage, disrupting testing workflows and requiring a manual restart of the application.

Technologies: github.com/SpectoLabs/hoverfly (Go). Vendors: Go.

Quick answers

Is CVE-2026-50013 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-50013 being exploited in the wild.
How severe is CVE-2026-50013?: High severity, with a CVSS score of 7.5, published 11 September 2026.
Which products and versions are affected?: github.com/SpectoLabs/hoverfly (Go) <= 1.12.7, SEMVER:introduced=0,fixed=1.12.8; SpectoLabs Hoverfly <= 1.12.7.
Is there a fix for CVE-2026-50013?: Yes. github.com/SpectoLabs/hoverfly (Go): upgrade to 1.12.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-50013 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-50013?: Check whether you run github.com/SpectoLabs/hoverfly (Go) or SpectoLabs Hoverfly at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/SpectoLabs/hoverfly (Go): upgrade to 1.12.8 or later
```
go get github.com/SpectoLabs/hoverfly@v1.12.8
```

Technical details

A race condition exists in the `AddDiff()` function within `core/hoverfly_service.go`. When Hoverfly is configured in 'Diff' mode, it attempts to write to the shared `responsesDiff` map without proper synchronization (mutex locking). Because Go's `net/http` server handles requests concurrently in separate goroutines, simultaneous requests trigger Go's built-in runtime race detector. This results in an unrecoverable 'fatal error: concurrent map read and map write', which immediately terminates the process. The vulnerability is fixed in version 1.12.8.

Affected products

SpectoLabs hoverfly <= 1.12.7

Identifiers

CVE-2026-50013
GHSA-qrh4-p6v4-mrfg
GO-2026-5977

Timeline

2026-06-03: patched: Version 1.12.8 released
2026-07-14: disclosed: GitHub Advisory published

References

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