Vulnerabilities

Telegram Desktop 2.9.2 contains a denial of service vulnerability that allows attackers to crash the application by sending an oversized message payload. Attackers can generate a 9 million byte buffer and paste it into the messaging interface to trigger an application crash.

EvilVideo vulnerability allows sending malicious apps disguised as videos in Telegram for Android application affecting versions 10.14.4 and older.

Telegram v9.6.3 on iOS allows attackers to hide critical information on the User Interface via calling the function SFSafariViewController.

Auth. (admin+) Stored Cross-Site Scripting (XSS) vulnerability in Marco Milesi Telegram Bot & Channel plugin <= 3.6.2 versions.

Telegram 9.3.1 and 9.4.0 allows attackers to access restricted files, microphone ,or video recording via the DYLD_INSERT_LIBRARIES flag.

Telegram Web 15.3.1 allows XSS via a certain payload derived from a Target Corporation website. NOTE: some third parties have been unable to discern any relationship between the Pastebin information and a possible XSS finding.

The Telegram application 7.5.0 through 7.8.0 for Android does not properly implement image self-destruction, a different vulnerability than CVE-2019-16248. After approximately two to four uses of the self-destruct feature, there is a misleading UI indication that an image was deleted (on both the sender and recipient sides). The images are still present in the /Storage/Emulated/0/Telegram/Telegram Image/ directory.

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

Telegram Web K Alpha 0.6.1 allows XSS via a document name.

A reordering issue exists in Telegram before 7.8.1 for Android, Telegram before 7.8.3 for iOS, and Telegram Desktop before 2.8.8. An attacker can cause the server to receive messages in a different order than they were sent a client.

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.

The Telegram app 7.6.2 for iOS allows remote authenticated users to cause a denial of service (application crash) if the victim pastes an attacker-supplied message (e.g., in the Persian language) into a channel or group. The crash occurs in MtProtoKitFramework. NOTE: the vendor's perspective is that "this behavior can't be considered a vulnerability."

The Terminate Session feature in the Telegram application through 7.2.1 for Android, and through 2.4.7 for Windows and UNIX, fails to invalidate a recently active session.

Telegram before 7.4 (212543) Stable on macOS stores the local copy of self-destructed messages in a sandbox path, leading to sensitive information disclosure.

Telegram Desktop through 2.4.3 does not require passcode entry upon pushing the Export key within the Export Telegram Data wizard. The threat model is a victim who has voluntarily opened Export Wizard but is then distracted. An attacker then approaches the unattended desktop and pushes the Export key. This attacker may consequently gain access to all chat conversation and media files.

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 Desktop through 2.0.1, Telegram through 6.0.1 for Android, and Telegram through 6.0.1 for iOS allow an IDN Homograph attack via Punycode in a public URL or a group chat invitation URL.

The Telegram application through 5.12 for Android, when Show Popup is enabled, might allow physically proximate attackers to bypass intended restrictions on message reading and message replying. This might be interpreted as a bypass of the passcode feature.

The "delete for" feature in Telegram before 5.11 on Android does not delete shared media files from the Telegram Images directory. In other words, there is a potentially misleading UI indication that a sender can remove a recipient's copy of a previously sent image (analogous to supported functionality in which a sender can remove a recipient's copy of a previously sent message).

The Privacy > Phone Number feature in the Telegram app 5.10 for Android and iOS provides an incorrect indication that the access level is Nobody, because attackers can find these numbers via the Group Info feature, e.g., by adding a significant fraction of a region's assigned phone numbers.

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.

An exploitable information disclosure vulnerability exists in the "Secret Chats" functionality of the Telegram Android messaging application version 4.9.0. The "Secret Chats" functionality allows a user to delete all traces of a chat, either by using a time trigger or by direct request. There is a bug in this functionality that leaves behind photos taken and shared on the secret chats, even after the chats are deleted. These photos will be stored in the device and accessible to all applications installed on the Android device.

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

An issue was discovered in the org.telegram.messenger application 4.8.11 for Android. The FingerprintManager class for Biometric validation allows authentication bypass through the callback method from onAuthenticationFailed to onAuthenticationSucceeded with null, because the fingerprint API in conjunction with the Android keyGenerator class is not implemented. In other words, an attacker could authenticate with an arbitrary fingerprint. NOTE: the vendor indicates that this is not an attack of interest within the context of their threat model, which excludes Android devices on which rooting has occurred

Telegram Desktop (aka tdesktop) 1.3.14, and Telegram 3.3.0.0 WP8.1 on Windows, leaks end-user public and private IP addresses during a call because of an unsafe default behavior in which P2P connections are accepted from clients outside of the My Contacts list.

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

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

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 0.10.19 uses 0755 permissions for $HOME/.TelegramDesktop, which allows local users to obtain sensitive authentication information via standard filesystem operations.