VULNERABILITY INTELLIGENCE

CVE-2018-20436

CVSS score8.1 HIGH
EPSS probability1.55%
CISA KEVNot currently listed
Published2018-12-24
Last modified2026-06-17
CVSS vectorCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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

Weakness classification

  • CWE-918: Server-Side Request Forgery (SSRF)

Primary references