Open Whisper Signal (aka Signal-Desktop) through 1.23.1 and the Signal Private Messenger application through 4.35.3 for Android are 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.

Signal Messenger for Android 4.24.8 may expose private information when using "disappearing messages." If a user uses the photo feature available in the "attach file" menu, then Signal will leave the picture in its own cache directory, which is available to any application on the system.

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.

An issue was discovered in the MULTIDOTS Add Social Share Messenger Buttons Whatsapp and Viber plugin 1.0.8 for WordPress. If an admin user can be tricked into visiting a crafted URL created by an attacker (via spear phishing/social engineering), the attacker can change the plugin settings via wp-admin/admin-post.php CSRF. There's no nonce or capability check in the whatsapp_share_setting_add_update() function.

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.

Untrusted search path vulnerability in Installer of IP Messenger for Win 4.60 and earlier allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.

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.

Multiple stack-based buffer overflows in Yahoo! Messenger 11.5.0.228 and earlier allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via the (1) shortcut or (2) title keys in an emoticons.xml file.

The Razer Comms - Gaming Messenger (aka com.razerzone.comms) application 1.3.07 for Android does not verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

Cross-site scripting (XSS) vulnerability in the Facebook app 14.0 and the Facebook Messenger app 10.0 for iOS allows remote attackers to inject arbitrary web script or HTML via a crafted filename extension that is improperly handled during MIME sniffing of chat traffic. NOTE: the vendor disputes the significance of this report, because the user must accept an interstitial warning before the HTML file content is rendered, and because the HTML content's origin is a sandbox domain