CVE-2026-59692: GStreamer DTLS Flaw Lets Attackers Crash RHEL WebRTC Systems

A newly disclosed vulnerability in GStreamer’s DTLS plugin allows remote, unauthenticated attackers to crash WebRTC-based media services by exploiting a stack buffer overflow triggered during certificate processing.

Tracked as CVE-2026-59692, the flaw carries a CVSS v3 base score of 7.5 and has been rated Important by Red Hat, affecting multiple versions of Red Hat Enterprise Linux and RHIVOS.

GStreamer DTLS Flaw

The root cause lies in how GStreamer’s DTLS plugin handles X.509 certificates during a DTLS handshake. When a peer certificate arrives, the plugin’s openssl_verify_callback function prints the certificate’s Subject Distinguished Name (DN) into a fixed-size, 2048-byte stack buffer. Critically, this operation lacks proper bounds checking.

An attacker can craft a malicious certificate with an oversized Subject DN, one that exceeds the 2048-byte allocation, and send it during handshake negotiation.

Since no authentication or user interaction is required to initiate a DTLS handshake, the attack surface is fully exposed on the network. The result: a stack buffer overflow that crashes the GStreamer process, triggering a denial-of-service (DoS) condition.

This issue is formally classified under CWE-121: Stack-Based Buffer Overflow, a weakness category historically responsible for some of the most severe memory corruption vulnerabilities in C-based software.

Despite the severity rating, Red Hat’s analysis confirms that remote code execution is not achievable here. Two protective factors neutralize exploitation attempts:

OpenSSL’s X509_NAME_print_ex() function escapes all binary and control characters into printable ASCII sequences before writing to the buffer, preventing attackers from injecting arbitrary executable bytes.
Red Hat builds compile with -fstack-protector-strong, meaning stack canaries detect overflow attempts and force a controlled process abort rather than allowing return-address corruption.

This combination limits the impact strictly to availability, reflected in the CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Confidentiality and integrity remain unaffected; availability impact is high.

“This vulnerability is a textbook example of defense-in-depth working as intended. The overflow exists, it’s remotely triggerable, and it will crash your service but character escaping and stack canaries turn what could have been a critical RCE into a manageable DoS issue. That distinction matters enormously for prioritization, but it shouldn’t be mistaken for ‘low risk.’ Any unauthenticated, zero-click crash vector in a production WebRTC pipeline deserves urgent patching attention, especially in media infrastructure that can’t tolerate downtime.”

The vulnerable component, gstreamer1-plugins-bad-free (and its legacy counterpart gstreamer-plugins-bad-free), ships across:

Red Hat Enterprise Linux 6, 7, 8, 9, and 10
RHIVOS (Red Hat In-Vehicle Operating System)

As of this writing, Red Hat has not issued fixing errata for any affected stream; all listed packages remain in “Affected” status with no patch reference.

Mitigation

No complete fix currently exists. Red Hat recommends these interim measures:

Remove the DTLS plugin shared object (libgstdtls.so) from /usr/lib64/gstreamer-1.0/ if WebRTC/DTLS functionality isn’t in use.
Restrict network access to DTLS/WebRTC endpoints via firewall rules limiting connections to trusted peers.
Place WebRTC services behind a reverse proxy or media server that can validate certificates before forwarding traffic to GStreamer.

Organizations running media servers, video conferencing backends, or IoT/automotive systems using RHIVOS with WebRTC pipelines should treat this as a priority patch-and-monitor item, particularly given the zero-click, unauthenticated attack path.