CVE-2026-28681: IRRd: web UI host header injection allows password reset poisoning via attacker-controlled email links

An attacker can manipulate the HTTP Host header on a password reset or account creation request. The confirmation link in the resulting email can then point to an attacker-controlled domain. Opening the link in the email is sufficient to pass the token to the attacker, who can then use it on the real IRRD instance to take over the account. A compromised account can then be used to modify RPSL objects maintained by the account’s mntners and perform other account actions.

If the user had two-factor authentication configured, which is required for users with override access, an attacker is not able to log in, even after successfully resetting the password.

This issue affects IRRD 4.5.0 and all 4.4.x versions prior to 4.4.5. IRRD 4.3 and earlier are not affected, as they did not include the web UI.