CVE-2022-29188

Smokescreen SSRF via deny list bypass (square brackets)

Acknowledgements

Thanks to Axel Chong for reporting the issue.

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The primary use case for Smokescreen is to prevent server-side request forgery (SSRF) attacks in which external attackers leverage the behavior of applications to connect to or scan internal infrastructure.

Smokescreen also offers an option to deny access to additional (e.g., external) URLs by way of a deny list. There was an issue in Smokescreen that made it possible to bypass the deny list feature by surrounding the hostname with square brackets (e.g. [example.com]).

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2022-29188 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no 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 (0.0.4); upgrading removes the vulnerable code path.

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Upgrade Smokescreen to version 0.0.4 or later.

1. What is CVE-2022-29188? CVE-2022-29188 is a medium-severity server-side request forgery (SSRF) vulnerability in github.com/stripe/smokescreen (go), affecting versions < 0.0.4. It is fixed in 0.0.4. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2022-29188? CVE-2022-29188 has a CVSS score of 5.3 (Medium). 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.
3. Which versions of github.com/stripe/smokescreen are affected by CVE-2022-29188? github.com/stripe/smokescreen (go) versions < 0.0.4 is affected.
4. Is there a fix for CVE-2022-29188? Yes. CVE-2022-29188 is fixed in 0.0.4. Upgrade to this version or later.
5. Is CVE-2022-29188 exploitable, and should I be worried? Whether CVE-2022-29188 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
6. What actually determines whether CVE-2022-29188 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.
7. How do I fix CVE-2022-29188? Upgrade github.com/stripe/smokescreen to 0.0.4 or later.

Other vulnerabilities in github.com/stripe/smokescreen