CVE-2026-50013
Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-362 CWE-820 |
| Vendor | spectolabs |
| Product | hoverfly |
| Published | Sep 11, 2026 |
| Last Updated | Sep 14, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
SpectoLabs / hoverfly
< 1.12.8