CVE-2026-109427 Telegram-Stremio 5.1.0 Broken Object Authorization via Stream IDs
Authenticated users can access private Telegram messages and thumbnails by forging stream IDs, bypassing authorization checks in the Telegram-Stremio addon.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-109427?
CVE-2026-109427 is a high-severity missing authorization vulnerability in weebzone Telegram-Stremio, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-109427?
How do I fix CVE-2026-109427?
No fix has been published for CVE-2026-109427 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-109427 being exploited?
There is no known exploitation of CVE-2026-109427 in the wild and no public exploit code.
Sources
Also known as GHSA-q45w-888c-vpfr.