What’s Vulnerable › Vulnerabilities

CVE-2021-32827: Arbitrary code execution in MockServer

• Severity: critical (CVSS 9.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-08-16 · updated 2026-06-17
• Weakness: CWE-74

Description

MockServer is open source software which enables easy mocking of any system you integrate with via HTTP or HTTPS. An attacker that can trick a victim into visiting a malicious site while running MockServer locally, will be able to run arbitrary code on the MockServer machine. With an overly broad default CORS configuration MockServer allows any site to send cross-site requests. Additionally, MockServer allows you to create dynamic expectations using Javascript or Velocity templates. Both engines may allow an attacker to execute arbitrary code on-behalf of MockServer. By combining these two issues (Overly broad CORS configuration + Script injection), an attacker could serve a malicious page so that if a developer running MockServer visits it, they will get compromised. For more details including a PoC see the referenced GHSL-2021-059.

Affected products

• mock-server mockserver: all versions
• Oracle Communications Cloud Native Core Policy: 1.14.0

References

• https://securitylab.github.com/advisories/GHSL-2021-059-mockserver/
• https://www.oracle.com/security-alerts/cpujan2022.html
• https://securitylab.github.com/advisories/GHSL-2021-059-mockserver/
• https://www.oracle.com/security-alerts/cpujan2022.html

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