# CVE-2026-50013

## Summary

- **CVE ID:** CVE-2026-50013
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-362, CWE-820
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 14, 2026

## Description

Hoverfly is an open source API simulation tool. Prior to version 1.12.8, when Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy requests are processed concurrently (the normal case for any proxy), the concurrent map writes trigger Go's built-in race detector which causes a `fatal error: concurrent map read and map write`, immediately killing the entire Hoverfly process. This is trivially exploitable by sending multiple simultaneous requests. Version 1.12.8 patches the issue.

## Affected Products

- SpectoLabs — hoverfly (< 1.12.8)

## References

- [CNA](https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-qrh4-p6v4-mrfg)
- [CNA](https://github.com/SpectoLabs/hoverfly/pull/1227)
- [CNA](https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.27%
- **EPSS Percentile:** 19.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._