CVE-2026-35208

lichess.org is the forever free, adless and open source chess server. Any approved streamer can inject arbitrary HTML into /streamer and the homepage “Live streams” widget by placing markup in their Twitch/YouTube stream title. CSP is present and blocks inline script execution, but the issue is still a server-side HTML injection sink. To trigger this, a Lichess account only needs to satisfy the normal streamer requirements and get approved. Per Streamer.canApply, that means an account older than 2 days with at least 15 games, or a verified/titled account. After moderator approval, once the streamer goes live, Lichess pulls the platform title and renders it into the UI as-is. No extra privileges are needed beyond a normal approved streamer profile. This vulnerability is fixed with commit 0d5002696ae705e1888bf77de107c73de57bb1b3.

The following products are affected by CVE-2026-35208 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-35208.

URL	Resource
https://github.com/lichess-org/lila/commit/0d5002696ae705e1888bf77de107c73de57bb1b3
https://github.com/lichess-org/lila/security/advisories/GHSA-v7gh-939r-pfjq
https://vimeo.com/1175908262