CVE-2026-109427 — Telegram-Stremio 5.1.0 Broken Object Authorization via Stream IDs
Telegram-Stremio through 5.1.0 contains a broken object-level authorization vulnerability that allows authenticated token holders to access arbitrary chat messages by forging un…
Published: 2026-10-12 · CVSS: 7.1 · CVSS 4.0
Telegram-Stremio through 5.1.0 contains a broken object-level authorization vulnerability that allows authenticated token holders to access arbitrary chat messages by forging unsigned, unauthenticated stream IDs decoded via encode_string/decode_string functions. Attackers can craft or enumerate sequential msg_id values and set a global flag in the stream_handler endpoint to route requests through the operator's personal Userbot account, exposing private channels, groups, and Saved Messages, while the unauthenticated thumb_handler endpoint further discloses thumbnails from those same chats without any token validation.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7