Telegram : Security Vulnerabilities, CVEs, CVSS score >= 7

An issue was discovered in Telegram Messenger 2.6 for iOS and 1.8.2 for Android. Secret chat messages are available in cleartext in process memory and a .db file.

The saveFile method in MediaController.java in the Telegram Messenger application before 2017-12-08 for Android allows directory traversal via a pathname obtained in a file-transfer request from a remote peer, as demonstrated by writing to tgnet.dat or tgnet.dat.bak.

Telegram Desktop (aka tdesktop) 1.3.14 might allow attackers to cause a denial of service (assertion failure and application exit) via an "Edit color palette" search that triggers an "index out of range" condition. NOTE: this issue is disputed by multiple third parties because the described attack scenario does not cross a privilege boundary

Telegram Desktop (aka tdesktop) 1.3.16 alpha, when "Use proxy" is enabled, sends credentials and application data in cleartext over the SOCKS5 protocol.

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

Telegram Desktop before 1.5.12 on Windows, and the Telegram applications for Android, iOS, and Linux, is vulnerable to an IDN homograph attack when displaying messages containing URLs. This occurs because the application produces a clickable link even if (for example) Latin and Cyrillic characters exist in the same domain name, and the available font has an identical representation of characters from different alphabets.

Telegram Desktop through 2.1.13 allows a spoofed file type to bypass the Dangerous File Type Execution protection mechanism, as demonstrated by use of the chat window with a filename that lacks an extension.

Telegram Android <7.1.0 (2090), Telegram iOS <7.1, and Telegram macOS <7.1 are affected by a Heap Buffer Overflow in the VGradientCache::generateGradientColorTable function of their custom fork of the rlottie library. A remote attacker might be able to overwrite heap memory out-of-bounds on a victim device via a malicious animated sticker.

Telegram Android <7.1.0 (2090), Telegram iOS <7.1, and Telegram macOS <7.1 are affected by a Stack Based Overflow in the gray_split_cubic function of their custom fork of the rlottie library. A remote attacker might be able to overwrite Telegram's stack memory out-of-bounds on a victim device via a malicious animated sticker.

Telegram Web K Alpha before 0.7.2 mishandles the characters in a document extension.