{"id":"CVE-2026-103974","published":"2026-10-14T19:17:07.843","lastModified":"2026-10-16T20:04:29.760","description":"lichess.org is the forever free, adless and open source chess server. Prior to commit c54596c9e1569d378fe20f80d4c790c6fdee54c4, a user who can add a chapter to a study can place attacker-controlled text in the PGN Annotator tag, which becomes Comment.Author.External and is returned verbatim by authorText. When a study node has at least two comments, ui/analyse/src/treeView/inlineView.ts interpolates that author string into HTML passed to the innerHTML hook without escaping it. Opening the affected study can therefore render stored attacker-controlled HTML and CSS for other viewers, including navigation to an attacker-controlled site, content spoofing, and CSS-based data exposure, although the site's content security policy blocks injected JavaScript. This vulnerability is fixed by commit c54596c9e1569d378fe20f80d4c790c6fdee54c4.","cvssScore":5.4,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","cwes":["CWE-79"],"vendors":[],"products":[],"references":[{"url":"https://github.com/lichess-org/lila/commit/c54596c9e1569d378fe20f80d4c790c6fdee54c4","tags":[]},{"url":"https://github.com/lichess-org/lila/security/advisories/GHSA-43g7-r6hp-ccf8","tags":[]},{"url":"https://github.com/lichess-org/lila/security/advisories/GHSA-43g7-r6hp-ccf8","tags":[]}],"exploitRefs":[{"url":"https://github.com/lichess-org/lila/commit/c54596c9e1569d378fe20f80d4c790c6fdee54c4","tags":[]},{"url":"https://github.com/lichess-org/lila/security/advisories/GHSA-43g7-r6hp-ccf8","tags":[]},{"url":"https://github.com/lichess-org/lila/security/advisories/GHSA-43g7-r6hp-ccf8","tags":[]}],"hasPoc":true,"ai":null}