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VulnerabilityPublished Updated

CVE-2026-50013: SpectoLabs hoverfly · Race Condition

Affects SpectoLabs hoverflySource CVE Database V5

0

Not known to be exploited · CVSS 7.5 High : upgrade to 1.12.8 soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.12.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade hoverfly and github.com/spectolabs/hoverfly to 1.12.8.

Affected software

ProductAffectedFixed in
SpectoLabshoverflyAffected
  • <1.12.8
Fixed in
  • 1.12.8
Gogithub.com/spectolabs/hoverflypkg:golang/github.com/spectolabs/hoverflyOther threatsAffected
  • <1.12.8
Fixed in
  • 1.12.8

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to Hoverfly version 1.12.8 or later, where the race condition has been fixed. No other mitigation is required as the patch addresses the root cause.

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.

References

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