Report: CVE-2026-35208 - lichess.org has an Unsanitized Stream Title Injection on /streamer

Report: CVE-2026-35208 - lichess.org has an Unsanitized Stream Title Injection on /streamer

CVE ID :CVE-2026-35208 Published : April 6, 2026, 9:16 p.m. | 14 minutes ago Description :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. Severity: 5.3 | MEDIUM Visit the link for more details, such as CVSS details, affected products, timeline, and more...

CVE Details

Severity
MEDIUM
Published
April 6, 2026