← Vulnerability feed

Vulnerability record · CVE-2021-32827 · published 16 August 2021

CVE-2021-32827: Mock-server mockserver injection vulnerability

Mock Server · Mockserver

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.

9.6 CVSS 3.1 Critical EPSS 2.2% · top 18.5% CWE-74 · InjectionCWE-79 · Cross-site scripting
9.6CVSS 3.1 base score, v2 6.8
2.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://securitylab.github.com/advisories/GHSL-2021-059-mockserver/ ExploitThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://securitylab.github.com/advisories/GHSL-2021-059-mockserver/ ExploitThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory

Track CVE-2021-32827 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2022-22963Spring Cloud Function routing expression SpEL injection RCESpring Cloud Function versions 3.1.6, 3.2.2 and older unsupported versions allow a user to supply a crafted SpEL expression as a routing-expression w…KEVEPSS 100%analysed9.8CVE-2022-22965Spring Framework data binding remote code execution (Spring4Shell)Spring MVC and Spring WebFlux applications on JDK 9+ can be exploited through data binding to achieve remote code execution. The known exploit path r…KEVEPSS 100%analysed8.5CVE-2021-39144XStream deserialization allows remote command executionXStream, a Java library that serializes objects to and from XML, can execute host commands when a remote attacker with sufficient rights manipulates …KEVEPSS 98%analysed9.8CVE-2021-3773Linux kernel information exposure vulnerabilityA flaw in netfilter could allow a network-connected attacker to infer openvpn connection endpoint information for further use in traditional network …EPSS 5.3%9.8CVE-2021-42392H2 database JNDI lookup flaw allows unauthenticated remote code executionThe org.h2.util.JdbcUtils.getConnection method in the H2 database accepts a driver class name and database URL from the caller. An attacker can suppl…EPSS 83%analysed9.8CVE-2021-23440Set-value project set-value type confusion vulnerabilityThis affects the package set-value before <2.0.1, >=3.0.0 <4.0.1. A type confusion vulnerability can lead to a bypass of CVE-2019-10747 when the user…EPSS 2.2%9.8CVE-2021-3520Lz4 project lz4 integer overflow vulnerabilityThere's a flaw in lz4. An attacker who submits a crafted file to an application linked with lz4 may be able to trigger an integer overflow, leading t…EPSS 3.2%8.8CVE-2021-39139Xstream unrestricted file upload vulnerabilityXStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to load a…EPSS 4.5%

Source: NIST National Vulnerability Database (record CVE-2021-32827), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.