CVE-2026-29068 in pjproject
Summary
by MITRE • 03/06/2026
PJSIP is a free and open source multimedia communication library written in C. Prior to version 2.17, there is a stack buffer overflow vulnerability when pjmedia-codec parses an RTP payload contain more frames than the caller-provided frames can hold. This issue has been patched in version 2.17.
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Analysis
by VulDB Data Team • 03/12/2026
The vulnerability identified as CVE-2026-29068 affects PJSIP, a widely-used open-source multimedia communication library implemented in C language. This library serves as a foundational component for real-time communication applications including VoIP systems, video conferencing platforms, and multimedia streaming services. The flaw exists in the pjmedia-codec module responsible for processing RTP payload data, which represents a critical component in multimedia communication protocols. The vulnerability specifically manifests when the library processes RTP packets containing multiple frames of data, creating a scenario where the internal buffer management fails to properly validate input boundaries.
The technical root cause of this stack buffer overflow stems from inadequate bounds checking within the frame parsing logic of the codec implementation. When processing RTP payloads, the library allocates a fixed-size buffer to hold frame data but fails to verify that the incoming data does not exceed the allocated buffer capacity. This occurs during the parsing of RTP payloads where multiple frames are present, and the caller-provided frame buffer size is insufficient to accommodate all frames contained within the payload. The vulnerability is classified as a classic stack-based buffer overflow with characteristics aligned to CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory locations.
The operational impact of this vulnerability presents significant security risks for systems utilizing PJSIP versions prior to 2.17. An attacker could potentially exploit this weakness by crafting malicious RTP packets containing an excessive number of frames that exceed the allocated buffer space. Successful exploitation could lead to arbitrary code execution, system crashes, or denial of service conditions within applications relying on PJSIP for multimedia communication. The vulnerability is particularly concerning in networked environments where RTP traffic flows through untrusted networks, as it could enable remote attackers to compromise the integrity and availability of communication systems. This type of vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access or execute malicious code.
The fix implemented in version 2.17 addresses this issue through enhanced input validation and proper buffer boundary checking within the RTP payload parsing routines. The patch ensures that the library validates the number of frames contained within RTP payloads against the available buffer capacity before attempting to copy frame data. This mitigation approach follows industry best practices for preventing buffer overflow vulnerabilities and aligns with the principle of least privilege in memory management. Organizations utilizing PJSIP should prioritize upgrading to version 2.17 or later to remediate this vulnerability, as the patch provides comprehensive protection against both local and remote exploitation scenarios. The vulnerability serves as a reminder of the critical importance of proper input validation in network protocols and the potential consequences of insufficient bounds checking in multimedia processing libraries.