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.
History

Mon, 14 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sat, 12 Sep 2026 18:45:00 +0000

Type Values Removed Values Added
First Time appeared Spectolabs
Spectolabs hoverfly
Vendors & Products Spectolabs
Spectolabs hoverfly

Fri, 11 Sep 2026 23:45:00 +0000

Type Values Removed Values Added
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.
Title Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode
Weaknesses CWE-362
CWE-820
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-11T21:27:40.296Z

Updated: 2026-09-14T18:17:21.942Z

Reserved: 2026-06-02T22:46:02.579Z

Link: CVE-2026-50013

cve-icon Vulnrichment

Updated: 2026-09-14T17:06:21.115Z

cve-icon NVD

Status : Deferred

Published: 2026-09-11T22:16:37.813

Modified: 2026-09-30T19:57:08.043

Link: CVE-2026-50013

cve-icon Redhat

No data.