fix: escape user input in notification content templates - #323
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Gi-ron merged 1 commit intoJul 28, 2026
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Discussion thread titles (and other user-controlled context fields — replier_name, author_name, username) were interpolated raw into notification.content via `str.format(**context)`. That output is rendered with Django's `|safe` filter in digest_content.html, which is included by both the email_digest and batched_email body templates, so a `<style>` block in a thread title survived into recipient inboxes as executable CSS on email open — enabling open-tracking, content spoofing, and phishing. Escape at the source: in `get_notification_content`, wrap every context value with `django.utils.html.escape` before `template.format(**context)`, exempting the two structural keys (`p`, `strong`) that content_templates use as HTML tag names. This defends every renderer of `notification.content` in one place. This is the incomplete-patch companion of GHSA-4xv3-5j4x-q8g4 (CVE-2026-42857), which sanitized the post body via `clean_thread_html_body()` but did not cover the title path. Fixes GHSA-rv5w-f4r5-h77g. (cherry picked from commit 08b719ce41bb369fa0cabbe8d0547124e64c8566) (cherry picked from commit 52f2b3b)
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Summary
get_notification_contentbeforestr.format(**context), fixing stored CSS injection in digest and batched notification emailsContext
The official fix landed on Ulmo, Verawood and master on July 13, 2026 but did not include Teak. Since
base_notification.pyis unchanged in our Teak branch relative to upstream, this cherry-pick applies cleanly with no conflicts.Discussion thread titles (and other user-controlled context fields —
replier_name,author_name,username) were interpolated raw intonotification.contentviastr.format(**context). That output is rendered with Django's|safefilter indigest_content.html, which is included by both theemail_digestandbatched_emailbody templates, so a<style>block in a thread title survived into recipient inboxes as executable CSS on email open — enabling open-tracking, content spoofing, and phishing.This is the incomplete-patch companion of GHSA-4xv3-5j4x-q8g4 (CVE-2026-42857), which sanitized the post body via
clean_thread_html_body()but did not cover the title path.