CVE-2018-20436

HIGH

Telegram 4.9.1 and Web 0.7.0 - Server-Side Request Forgery via URL Preview in Secret Chat

Title source: manual
STIX 2.1

Description

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

References (2)

Core 2
Core References

Scores

CVSS v3 8.1
EPSS 0.0155
EPSS Percentile 72.1%
Attack Vector NETWORK
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-918
Status published
Products (2)
telegram/telegram 4.9.1
telegram/web 0.7.0
Published Dec 24, 2018
Tracked Since Feb 18, 2026