Impact

GoCD versions from 19.4.0 to 23.5.0 (inclusive) are potentially vulnerable to a reflected XSS vulnerability on the loading page displayed while GoCD is starting, via abuse of a redirect_to query parameter with inadequate validation.

Attackers could theoretically abuse the query parameter to steal session tokens or other values from the user's browser. In practice exploiting this to perform privileged actions is likely impossible because:

• the target user would need to be triggered to open an attacker-crafted link in the period where the server is starting up (but not completely started) requiring chaining with a separate denial-of-service vulnerability
• GoCD server restarts invalidate earlier session tokens (i.e GoCD does not support persistent sessions), so a stolen session token from an earlier session would be unusable once the server has completed restart, and thus any executed XSS would be done within a logged-out context.

Patches

Fixed in GoCD 24.1.0.

Workarounds

None likely necessary.

It is technically possible in earlier GoCD versions to override the loading page with an earlier version which is not vulnerable, by starting GoCD with the Java system property override as either

• -Dloading.page.resource.path=/loading_pages/default.loading.page.html (simpler early version of loading page without GoCD introduction) or
• -Dloading.page.resource.path=/does_not_exist.html (to display a simple message with no interactivity)

References

• Release Notes
• Tagged Release
• Patch
• NIST CVE

For more information

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