The secret chat feature in Telegram 4.9.1 for Android has a side channel in which Telegram servers send GET requests for URLs typed while composing a chat message, before that chat message is sent. There are also GET requests to other URLs on the same web server. This also affects one or more other Telegram products, such as Telegram Web-version 0.7.0. In addition, it can be interpreted as an SSRF issue. NOTE: a third party has reported that potentially unwanted behavior is caused by misconfiguration of the Secret chats > Preview links setting
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Telegram | Telegram | 4.9.1 (including) | 4.9.1 (including) |
| Web | Telegram | 0.7.0 (including) | 0.7.0 (including) |