CVE-2021-32827

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.

How to fix CVE-2021-32827

No fixed version has been published yet. Mitigate by removing the affected package or applying upstream guidance from the references below.

• —no fix listed

Is CVE-2021-32827 being exploited?

Low — EPSS is 0.8%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• from 0, <= 5.11.2

CVSS scores

References (4)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-32827
• ADVISORYsecuritylab.github.com/advisories/GHSL-2021-059-mockserver
• PATCHgithub.com/mock-server/mockserver
• WEBwww.oracle.com/security-alerts/cpujan2022.html