Task titles, project titles, team names, doer/assignee names, and API
token titles were interpolated raw into Line(...) calls whose content is
rendered to HTML by goldmark and then sanitized with bluemonday UGCPolicy.
UGCPolicy intentionally allows safe <a href> and <img src> with
http/https URLs, so a title containing Markdown link or image syntax
would survive sanitization as a working phishing link or tracking pixel
in a legitimate Vikunja email.
Introduce notifications.EscapeMarkdown, which prefixes every CommonMark
§2.4 backslash-escapable ASCII punctuation character — including '<' so
autolinks like `<https://evil.com>` are neutralized before reaching
goldmark — with a backslash. Apply it to every user-controlled argument
of every Line(...) call in pkg/models that feeds into an i18n template,
and to the hand-built "* [title](url) (project)" Markdown link in the
overdue-tasks digest notification.
Also escape the migration error string in MigrationFailedNotification,
an additional sink not listed in the advisory (error messages can carry
user-controlled content from the external migration source).
Subject(...), Greeting(...), and CreateConversationalHeader(...) are
left unchanged: Subject is passed directly to the mail library and is
not markdown-rendered, Greeting is rendered via html/template's built-in
HTML escaping without markdown, and the conversational header is
sanitized as raw HTML by bluemonday in mail_render.go.
Fixes GHSA-45q4-x4r9-8fqj.
This change introduces notifications via mail when a migration fails. It will contain the error message and a hint to post it in the forum when Sentry is disabled, otherwise the error message will be sent directly to sentry and the notification will inform accordingly.
I've tried to balance "this thing failed, go figure it out" with "here is what we know and how you can get help", we'll see how well that approach works.
