CVE-2014-7221 in TeamSpeak
Summary
by MITRE
TeamSpeak Client 3.0.14 and earlier allows remote authenticated users to cause a denial of service (buffer overflow and application crash) by connecting to a channel with a different client instance, and placing crafted data in the Chat/Server tab containing [img]//http:// substrings.
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Analysis
by VulDB Data Team • 07/26/2025
The vulnerability CVE-2014-7221 represents a critical buffer overflow flaw in TeamSpeak Client versions 3.0.14 and earlier, specifically affecting the client-side application's handling of multimedia content within chat interfaces. This issue manifests when authenticated users connect to channels and manipulate the Chat/Server tab by inserting specially crafted data containing [img]//http:// substrings, which triggers an exploitable condition that can be leveraged for denial of service attacks. The vulnerability operates at the application layer and demonstrates a classic improper input validation flaw that allows attackers to manipulate the client's memory management routines.
The technical implementation of this vulnerability stems from the client's insufficient validation of image URL parameters within the chat interface, particularly when processing the [img] tag syntax. When a malicious user places crafted data containing [img]//http:// substrings into the chat tab, the client application attempts to parse and render these image references without adequate bounds checking or memory allocation safeguards. This processing error creates a condition where the application's buffer handling mechanisms fail to properly manage memory allocation for the parsed image data, leading to stack corruption and subsequent application crash. The flaw specifically targets the client-side rendering engine's handling of remote image references, making it particularly dangerous in multi-user channel environments where malicious actors can exploit this vulnerability through legitimate network connections.
From an operational perspective, this vulnerability enables authenticated remote attackers to effectively perform denial of service attacks against TeamSpeak client instances, compromising the availability of communication services for legitimate users. The attack requires only a valid client login and access to a channel, making it particularly dangerous in collaborative environments where multiple users rely on consistent communication channels. The impact extends beyond simple service disruption as the application crash can potentially affect the entire client session, forcing users to restart their applications and potentially lose unsaved chat history or connection state information. This vulnerability particularly affects enterprise environments where TeamSpeak is used for team collaboration, gaming communities, and professional communication platforms where uninterrupted service availability is critical.
The vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1499.004 for network denial of service attacks. Organizations should implement immediate mitigations including mandatory client version updates to patched versions, network-level filtering of suspicious chat content, and implementation of automated monitoring for anomalous client behavior patterns. Additionally, administrators should consider implementing client-side security policies that restrict the execution of external image references within chat interfaces and establish regular security assessments to identify similar vulnerabilities in other multimedia processing components. The incident highlights the importance of input validation in client-side applications and underscores the necessity of regular security updates to protect against known vulnerabilities that can be exploited for service disruption attacks.