GHSA-xmg8-99r8-jc2j Login screen allows message spoofing if SSO is enabled

• Go github.com/argoproj/argo-cd/v2: >= 2.3.0, < 2.3.4 → fixed in 2.3.4 • Go github.com/argoproj/argo-cd/v2: >= 2.2.0, < 2.2.9 → fixed in 2.2.9 • Go github.com/argoproj/argo-cd/v2: >= 2.0.0, < 2.1.15 → fixed in 2.1.15 • Go github.com/argoproj/argo-cd: < 2.1.15 → fixed in 2.1.15

Impact A vulnerability was found in Argo CD that allows an attacker to spoof error messages on the login screen when SSO is enabled. In order to exploit this vulnerability, an attacker would have to trick the victim to visit a specially crafted URL which contains the message to be displayed. As far as the research of the Argo CD team concluded, it is not possible to specify any active content (e.g. Javascript) or other HTML fragments (e.g. clickable links) in the spoofed message. Patched versions A patch for this vulnerability has been released in the following Argo CD versions: • v2.3.4 • v2.2.9 • v2.1.15 Workarounds No workaround available. Mitigations It is advised to update to an Argo CD version containing a fix for this issue (see *Patched versions* above). Credits This vulnerability was discovered by Naufal Septiadi () and reported to us in a responsible way. For more information • Open an issue in the Argo CD issue tracker or discussions • Join us on Slack in channel #argo-cd