CVE-2026-54632 in SIPSorcery
Summary
by MITRE • 09/14/2026
SIPSorcery is a WebRTC, SIP, and VoIP library for C# and .NET. Prior to 10.0.9, RTPChannel.OnRTPPacketReceived and the STUNAttribute.ParseMessageAttributes, STUNXORAddressAttribute, and STUNAddressAttribute parsing path index untrusted bytes without sufficient length checks, while UdpReceiver.EndReceiveFrom closes the channel when those operations raise a non-socket exception. A remote party can send a single short RTP packet or malformed zero-to-seven-byte STUN address attribute to the shared RTP/ICE socket, including during ICE connectivity checks before DTLS or STUN MESSAGE-INTEGRITY verification, and terminate the active RTP or WebRTC media session. The attacker must reach or learn the advertised ephemeral RTP/ICE port, but no authentication or user interaction is required, and the impact is limited to availability. This issue is fixed in version 10.0.9.
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Analysis
by VulDB Data Team • 09/14/2026
SIPSorcery serves as a foundational library for implementing WebRTC, SIP, and VoIP functionalities within C# and .NET environments, facilitating real-time communication protocols that rely heavily on UDP-based transport mechanisms such as RTP and STUN. The vulnerability identified in versions prior to 10.0.9 stems from insufficient input validation during the parsing of network packets, specifically affecting how untrusted bytes are processed by critical components like RTPChannel.OnRTPPacketReceived and various STUN attribute parsers including STUNAttribute.ParseMessageAttributes, STUNXORAddressAttribute, and STUNAddressAttribute. These methods fail to perform adequate length checks on incoming data before attempting to access array indices or parse structural elements based on byte offsets derived from the packet content. This lack of boundary verification creates a classic out-of-bounds read condition where malformed input can trigger exceptions that are not properly handled within the application logic.
The operational impact of this flaw is significant for availability, as it allows a remote attacker to terminate active RTP or WebRTC media sessions with minimal effort. By sending a single short RTP packet or a specifically crafted STUN address attribute containing between zero and seven bytes, an adversary can induce exceptions in the parsing routines. Crucially, these attacks are effective even before DTLS encryption layers or STUN MESSAGE-INTEGRITY authentication checks are performed during ICE connectivity checks. This means that the vulnerability is exploitable without requiring any form of user interaction or prior authentication, provided the attacker knows or can discover the advertised ephemeral RTP or ICE port associated with the target service. The consequence is a denial of service where legitimate communication channels are abruptly closed due to unhandled non-socket exceptions in the UdpReceiver.EndReceiveFrom method which terminates the channel upon encountering such errors.
This vulnerability aligns with CWE-125, Out-of-bounds Read, as it involves accessing memory or data structures beyond their intended boundaries due to missing length validations. From a threat modeling perspective utilizing the MITRE ATT&CK framework, this behavior is consistent with techniques found under Tactic TA0004 Impact and specifically relates to Availability impact categories such as Service Stop (T1499) where an attacker disrupts service availability by exploiting software flaws that cause crashes or unexpected termination of processes. The attack vector is classified as Network-based because it requires only network access to the specific port, making it a remote code execution alternative focused purely on disrupting connectivity rather than gaining control over the system.
Mitigation strategies primarily involve upgrading to version 10.0.9 or later where these parsing routines have been corrected to include robust length checks before processing untrusted input data. For organizations unable to immediately patch their systems, implementing network-level filtering rules can provide temporary relief by restricting UDP traffic on RTP and ICE ports to known trusted IP addresses only. Additionally, deploying intrusion detection signatures that monitor for abnormally short STUN packets or malformed RTP headers destined for VoIP infrastructure may help in identifying attempted exploitation activities. Ensuring that exception handling logic does not blindly close entire communication channels upon encountering parsing errors is also a recommended defensive coding practice to maintain service resilience against similar future vulnerabilities.