{"cve":"CVE-2018-20436","nvd":{"published":"2018-12-24T20:29:00.287","modified":"2026-06-17T01:52:50.410","status":"Modified","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","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1},"cwes":["CWE-918"],"references":["https://misteralfa-hack.blogspot.com/2018/12/abusando-de-telegram-para-conseguir-una.html","https://misteralfa-hack.blogspot.com/2018/12/telegram-siempre-in-middle.html","https://misteralfa-hack.blogspot.com/2018/12/abusando-de-telegram-para-conseguir-una.html","https://misteralfa-hack.blogspot.com/2018/12/telegram-siempre-in-middle.html"],"products":["telegram:telegram","telegram:web"],"source":"nvd","synced_at":"2026-10-19T20:54:36.112582389+00:00"},"epss":{"cve":"CVE-2018-20436","score":0.01554,"percentile":0.75144,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}