CVE-2026-50013

Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode

Published Sep 11, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-qrh4-p6v4-mrfg Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode
History
Type Values Removed Values Added
Metrics ssvc

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

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

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 14, 2026, 6:17 PM
Reserved
Jun 2, 2026, 10:46 PM
Status
Deferred
Published
Sep 11, 2026, 10:16 PM
Modified
Sep 30, 2026, 7:57 PM