In haml versions prior to version 5.0.0.beta.2, when using user input to perform tasks on the server, characters like < > " ' must be escaped properly. In this case, the ' character was missed. An attacker can manipulate the input to introduce additional attributes, potentially executing code.
{
"severity": "MODERATE",
"github_reviewed_at": "2019-10-16T15:18:02Z",
"nvd_published_at": "2019-10-15T18:15:00Z",
"github_reviewed": true,
"cwe_ids": [
"CWE-79"
]
}