🛡️ CVE-2026-35208
🟡 CVSS 5.4 — Medium ⚠️ Exploit Public CWE-79 NVD
5.4
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

Details

Severity MEDIUM
CVSS Score 5.4
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CWE CWE-79
Public Exploit ⚠️ Yes
Source NVD
Published 2026-04-06
Updated 2026-06-02
Modified 2026-04-16

Affected Packages

Software From version Fixed in
lila 2026-03-31

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