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No exploitation reported

CVE-2018-20436

No exploitation reported by the sources we read.

  • Published2018-12-24
  • WeaknessCWE-918

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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

Timeline

dates in UTC
  1. 2018-12-2420:29CVE publishedNVD

Versions per branch

NVD
Telegram
BranchAffectedFixed in
4.9= 4.9.1no fix published
Telegram web
BranchAffectedFixed in
0.7= 0.7.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2018-12-24
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-53m8-q7p6-6hq3

Frequently asked questions

What is CVE-2018-20436?

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

Is CVE-2018-20436 actively exploited?

Active exploitation of CVE-2018-20436 has not been confirmed. Its EPSS score was 1.6% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-20436?

CVE-2018-20436 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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