GStreamer DTLS Plugin Stack Buffer Overflow

Executive Summary

CVE-2026-59692 is a stack buffer overflow vulnerability found in GStreamer's DTLS plugin. During the DTLS handshake process, the peer certificate's Subject Distinguished Name (DN) is printed into a fixed-size 2048-byte stack buffer without proper bounds checking. If a remote attacker sends a certificate with an excessively long Subject DN, it can overflow this buffer.

This overflow causes the process to crash, resulting in a denial of service. The vulnerability occurs in the openssl_verify_callback() function and affects GStreamer versions up to 1.28.3.

Although the overflow content is limited to printable ASCII characters and the stack canary prevents remote code execution, the vulnerability can be exploited by unauthenticated remote DTLS-SRTP/WebRTC peers during the handshake without user interaction.

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Impact Analysis

This vulnerability can cause a denial of service by crashing the affected process during the DTLS handshake. An attacker can remotely trigger this crash by sending a specially crafted certificate with an oversized Subject DN.

While remote code execution is not possible due to stack canary protections, the denial of service can disrupt services relying on GStreamer's DTLS plugin, potentially affecting availability.

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Detection Guidance

This vulnerability occurs during the DTLS handshake when a peer certificate with an excessively long Subject Distinguished Name (DN) is processed by GStreamer's DTLS plugin. Detection involves monitoring for crashes or denial of service symptoms in applications using GStreamer DTLS plugin versions up to 1.28.3.

Since the vulnerability is triggered by a remote unauthenticated DTLS handshake with a crafted certificate, network detection can focus on analyzing DTLS handshake traffic for unusually large Subject DN fields in certificates.

Specific commands to detect this vulnerability are not provided in the available resources.

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Mitigation Strategies

Immediate mitigation involves updating GStreamer to version 1.28.5 or later, where the fix for this vulnerability has been merged.

Until the update can be applied, consider restricting or monitoring incoming DTLS handshake traffic to prevent unauthenticated remote peers from sending crafted certificates with oversized Subject DNs.

Additionally, monitoring application logs for crashes related to DTLS handshakes can help identify exploitation attempts.

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Compliance Impact

The vulnerability causes a denial of service through a stack buffer overflow in GStreamer's DTLS plugin during a DTLS handshake. It does not result in data confidentiality or integrity loss, as it does not allow remote code execution or unauthorized data access.

Because the impact is limited to denial of service without compromise of sensitive data, the vulnerability itself does not directly imply non-compliance with data protection regulations such as GDPR or HIPAA. However, denial of service could affect availability requirements under these standards if exploited in a production environment.

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