Unspecified vulnerability in Microsoft Office Communications Server (OCS), Office Communicator, and Windows Live Messenger allows remote attackers to cause a denial of service (crash) via a crafted Real-time Transport Control Protocol (RTCP) receiver report packet.

An ActiveX control (Messenger.UIAutomation.1) in Windows Messenger 4.7 and 5.1 is marked as safe-for-scripting, which allows remote attackers to control the Messenger application, and "change state," obtain contact information, and establish audio or video connections without notification via unknown vectors.

Buffer overflow in the CoVideoWindow.ocx ActiveX control 5.0.907.1 in Eyeball MessengerSDK, as used in products such as SiOL Komunikator 1.3, allows remote attackers to execute arbitrary code via a large argument supplied to the BGColor method. NOTE: this might only be a vulnerability in certain insecure configurations of Internet Explorer.

Novell GroupWise Messenger (GWIM) before 2.0.3 Hot Patch 1 allows remote attackers to cause a denial of service (crash) via a long user ID, possibly involving a popup alert. NOTE: it is not clear whether this issue crosses privilege boundaries.

Multiple stack-based buffer overflows in Novell GroupWise Messenger (GWIM) Client before 2.0.3 HP1 for Windows allow remote attackers to execute arbitrary code via "spoofed server responses" that contain a long string after the NM_A_SZ_TRANSACTION_ID field name.

The DownloaderActiveX Control (DownloaderActiveX.ocx) in Icona SpA C6 Messenger 1.0.0.1 allows remote attackers to force the download and execution of arbitrary files via a URL in the propDownloadUrl parameter with the propPostDownloadAction parameter set to "run."

Stack-based buffer overflow in the AntServer module (AntServer.exe) in BigAnt IM Server in BigAnt Messenger 2.2 allows remote attackers to execute arbitrary code via a long URI in a request to TCP port 6080. NOTE: some of these details are obtained from third party information.

The gg protocol handler in Gadu-Gadu, when this product is installed but not running, does not properly handle the skin attribute, which allows remote attackers to cause a denial of service (resource consumption) via unspecified network traffic.

Multiple buffer overflows in the HandleEmotsConfig function in the GG Client in Gadu-Gadu 7.7 Build 3669 allow user-assisted remote attackers to execute arbitrary code or cause a denial of service (gg.exe process crash) via a long string in an emots.txt file.

Gadu-Gadu does not properly perform protocol handling, which allows remote attackers to conduct cross-site request forgery (CSRF) attacks and add arbitrary user accounts or cause a denial of service as administrators via an unspecified "crafted link," possibly related to the gg protocol.