CVE-2026-53963

Description

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, a malicious second factor name on an attacker-controlled account was not escaped in the delete confirmation dialog, allowing stored cross-site scripting when an administrator impersonated that account. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

References

• https://github.com/discourse/discourse/commit/40de62cddadc65c328a1028ab999f3fa94adbfed
• https://github.com/discourse/discourse/commit/529e17d4d570a48972e7cf64720e5dd1fdf23ca8
• https://github.com/discourse/discourse/commit/d92973e51a46cf6dd20c71e6068e6769b67eea5b
• https://github.com/discourse/discourse/commit/daea5214d833eacbdd3b1a78d99eb14e9cabd915
• https://github.com/discourse/discourse/releases/tag/v2026.1.5