Synchronization Flaw in Hoverfly API Simulation Tool
CVE-2026-50013

7.5HIGH

Key Information:

Vendor

Spectolabs

Status
Hoverfly
Vendor
CVE Published:
11 September 2026

What is CVE-2026-50013?

Hoverfly, an open source API simulation tool by SpectoLabs, is affected by a concurrency issue that occurs in Diff mode. The 'AddDiff()' function improperly interacts with shared resources, leading to unsynchronized access to the 'responsesDiff' map. This flaw can result in a race condition when multiple proxy requests are processed simultaneously, leading to fatal errors that crash the entire Hoverfly process. The vulnerability can be easily exploited by sending concurrent requests to the application. Users are advised to upgrade to version 1.12.8 or later, which includes a fix for this critical flaw.

Affected Version(s)

hoverfly < 1.12.8

References

https://github.com/SpectoLabs/hoverfly/security/advisorie...
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https://github.com/SpectoLabs/hoverfly/pull/1227
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https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8
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CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.