The User-Agent
and Server
header parsers are susceptible to a fatal error on certain inputs. In http4s, modeled headers are lazily parsed, so this only applies to services that explicitly request these typed headers.
val unsafe: Option[`User-Agent`] = req.headers.get(`User-Agent`)
val unsafe: Option[`User-Agent`] = req.headers.get[`User-Agent`]
val alsoUnsafe: Option[`Server`] = req.headers.get[Server]
Fixes are released in 0.21.34, 0.22.15, 0.23.17, and 1.0.0-M38.
val safe: Option[Header] = req.headers.get("User-Agent".ci)
// but don't do this
val unsafe = header.map(_.parsed)
val safe: Option[Header] = req.headers.get(ci"User-Agent")
{ "nvd_published_at": "2023-01-04T16:15:00Z", "github_reviewed_at": "2023-01-06T20:24:36Z", "severity": "HIGH", "github_reviewed": true, "cwe_ids": [ "CWE-20" ] }