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Fencer Vulns
high 8.8

CVE-2026-59148 json

Mockoon: Unauthenticated admin API + wildcard CORS allows mock-state hijack and secret theft

published 2026-07-09 4 mo ago modified 2026-09-11 58 d ago also GHSA-rqx4-3f6q-3x2v , EUVD-2026-42683

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

Mockoon provides way to design and run mock APIs. Prior to 9.7.0, Mockoon's admin API in commons-server/src/libs/server/admin-api.ts is mounted on the same Express listener as user-defined mock routes, enabled by default in shipped runtimes, serves Access-Control-Allow-Origin: * with write methods allowed, and has no authentication. Any unauthenticated caller who can reach the mock server port can read MOCKOON_* environment variables, write arbitrary process environment variables through /mockoon-admin/env-vars, rewrite mock route bodies, statuses, and headers through PUT /mockoon-admin/environment, read transaction logs and SSE streams, and purge state. This issue is fixed in version 9.7.0.

Patch / fix

  • npm @mockoon/commons-server 9.7.0
  • npm @mockoon/cli 9.7.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/mockoon/mockoon/security/advisories/GHSA-rqx4-3f6q-3x2v referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm @mockoon/commons-server
<9.7.0
9.7.0
npm @mockoon/cli
<9.7.0
9.7.0

Affected products

  • mockoon mockoon

Classification

Weakness
  • CWE-306 Missing Authentication for Critical Functionality
  • CWE-352 Cross-Site Request Forgery
  • CWE-732 Incorrect Permission Assignment for Critical Resource
  • CWE-942 Permissive Cross-domain Security Policy with Untrusted Domains

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.