Summary
Domain restrictions bypass via DNS Rebinding in WireMock and WireMock Studio webhooks, proxy and recorder modes
Affected versions
- WireMock 3,x until 3.0.3 (security patch), on default settings in environments with access to the network
- WireMock 2.x until 2.35.1 (security patch), on default settings in environments with access to the network
- Python WireMock until 2.6.1
- WireMock Studio - all versions, this proprietary product was discontinued in 2022
Workarounds
For WireMock:
- Option 1: Configure WireMock to use IP addresses instead of the domain names in the outbound URLs subject to DNS rebinding
- Option 2: Use external firewall rules to define the list of permitted destinations
For WireMock Studio: N/A. Switch to another distribution, there will be no fix provided. The vendor of former WireMock Studio recommends migration to WireMock Cloud
References
- CVE-2023-41327 - Related issue in the WireMock Webhooks Extension
Impact
The proxy mode of WireMock, can be protected by the network restrictions configuration, as documented in Preventing proxying to and recording from specific target addresses. These restrictions can be configured using the domain names, and in such a case the configuration is vulnerable to the DNS rebinding attacks. A similar patch was applied in WireMock 3.0.0-beta-15 for the WireMock Webhook Extensions.
The root cause of the attack is a defect in the logic which allows for a race condition triggered by a DNS server whose address expires in between the initial validation and the outbound network request that might go to a domain that was supposed to be prohibited. Control over a DNS service is required to exploit this attack, so it has high execution complexity and limited impact.
CVE-2023-41329 has a CVSS score of 3.9 (Low). The vector is reachable from an adjacent network, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.0.3, 2.35.1, 2.6.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
- WireMock 3.0.3 + the 3.0.3-1 Docker image
- WireMock 2.35.1 + the 2.35.1-1 Docker image - backport to WireMock 2.x
- Python WireMock 2.6.1
Frequently Asked Questions
- What is CVE-2023-41329? CVE-2023-41329 is a low-severity security vulnerability in org.wiremock:wiremock-standalone (maven), affecting versions < 3.0.3. It is fixed in 3.0.3, 2.35.1, 2.6.1.
- How severe is CVE-2023-41329? CVE-2023-41329 has a CVSS score of 3.9 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2023-41329?
org.wiremock:wiremock-standalone(maven) (versions < 3.0.3)org.wiremock:wiremock(maven) (versions < 3.0.3)com.github.tomakehurst:wiremock-jre8(maven) (versions < 2.35.1)com.github.tomakehurst:wiremock-jre8-standalone(maven) (versions < 2.35.1)wiremock(pip) (versions < 2.6.1)
- Is there a fix for CVE-2023-41329? Yes. CVE-2023-41329 is fixed in 3.0.3, 2.35.1, 2.6.1. Upgrade to this version or later.
- Is CVE-2023-41329 exploitable, and should I be worried? Whether CVE-2023-41329 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-41329 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2023-41329?
- Upgrade
org.wiremock:wiremock-standaloneto 3.0.3 or later - Upgrade
org.wiremock:wiremockto 3.0.3 or later - Upgrade
com.github.tomakehurst:wiremock-jre8to 2.35.1 or later - Upgrade
com.github.tomakehurst:wiremock-jre8-standaloneto 2.35.1 or later - Upgrade
wiremockto 2.6.1 or later
- Upgrade