CVE-2021-23347

Workarounds

• Do not use SSO with the CLI when you don't trust your SSO provider

If you have any questions or comments about this advisory:

• Open an issue in the Argo CD issue tracker or discussions
• Join us on Slack in channel #argo-cd

Credits

The issue was found during static code scanning with CodeQL and fixed by the Argo CD team. While we believed that a rogue SSO provider would pose a severe threat by itself, we fixed it like a regular bug.

The Argo CD team would like to thank Adam Gold of Snyk (https://snyk.io) for stepping up and classifying this correctly as a security issue and for his help in determining its severity. Also, Snyk kindly reserved and provided the CVE for this vulnerability.

We fully agree with Adam that this bug is a security vulnerability and justifies publishing a SA, to provide our community and users full transparancy.

When using SSO with the Argo CD CLI, a malicious SSO provider could have sent specially crafted error message that would result in XSS on the client by means of executing arbitrary JavaScript code.

We believe the exploitation of this vulnerability is only be possible when Argo CD is connected to a compromised/malicious SSO provider.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2021-23347 has a CVSS score of 4.7 (Medium). The vector is network-reachable, 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 (1.7.13, 1.8.6); upgrading removes the vulnerable code path.

Kodem intelligence

A patch for this vulnerability is available with the v1.8.7 and v1.7.14 releases of Argo CD.

1. What is CVE-2021-23347? CVE-2021-23347 is a medium-severity cross-site scripting (XSS) vulnerability in github.com/argoproj/argo-cd/v2 (go), affecting versions < 1.7.13. It is fixed in 1.7.13, 1.8.6. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2021-23347? CVE-2021-23347 has a CVSS score of 4.7 (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/argoproj/argo-cd/v2 are affected by CVE-2021-23347? github.com/argoproj/argo-cd/v2 (go) versions < 1.7.13 is affected.
4. Is there a fix for CVE-2021-23347? Yes. CVE-2021-23347 is fixed in 1.7.13, 1.8.6. Upgrade to this version or later.
5. Is CVE-2021-23347 exploitable, and should I be worried? Whether CVE-2021-23347 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-2021-23347 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-2021-23347?
   • Upgrade github.com/argoproj/argo-cd/v2 to 1.7.13 or later
   • Upgrade github.com/argoproj/argo-cd/v2 to 1.8.6 or later