CVE-2018-20436

Name: CVE-2018-20436
Creator: NVD / NIST
Published: 2018-12-24T20:29:00.287+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 1.55%

Last modified Jun 17, 2026

CVE-2018-20436 is a vulnerability of currently unknown severity. 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. EPSS estimates a 1.55% chance of exploitation in the next 30 days.

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

Metrics

EPSS Probability

1.55%

72.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-918

Affected Software

Vendor	Product	Versions
Telegram	Telegram	4.9.1
Telegram	Web	0.7.0

References

https://misteralfa-hack.blogspot.com/2018/12/abusando-de-telegram-para-conseguir-una.htmlExploit, Third Party Advisory
https://misteralfa-hack.blogspot.com/2018/12/telegram-siempre-in-middle.htmlExploit, Third Party Advisory
https://misteralfa-hack.blogspot.com/2018/12/abusando-de-telegram-para-conseguir-una.htmlExploit, Third Party Advisory
https://misteralfa-hack.blogspot.com/2018/12/telegram-siempre-in-middle.htmlExploit, Third Party Advisory

Timeline

Published: Dec 24, 2018
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2018-20436?

How severe is CVE-2018-20436?

Severity scoring for CVE-2018-20436 is pending analysis. The EPSS model estimates a 1.55% probability of exploitation in the next 30 days.

How do I fix CVE-2018-20436?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-20436?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST