CVE-2026-59692

A stack buffer overflow vulnerability was found in GStreamer's DTLS plugin. During a DTLS handshake, the peer certificate Subject Distinguished Name is printed into a fixed-size 2048-byte stack buffer without bounds checking. A remote unauthenticated attacker can send a certificate with an oversized Subject DN that exceeds the buffer, causing a stack buffer overflow and process crash, resulting in denial of service.

This vulnerability is rated as Important severity because it is remotely triggerable without authentication or user interaction during a DTLS handshake. However, the actual impact is limited to denial of service. Remote code execution is not achievable because X509_NAME_print_ex() escapes all binary and control characters to printable ASCII sequences, preventing arbitrary byte injection into the overflow. Combined with stack canary protection (-fstack-protector-strong) in Red Hat builds, return address corruption cannot be exploited. The DTLS plugin is shipped as part of gstreamer1-plugins-bad-free in Red Hat Enterprise Linux 8, 9, 10, and RHIVOS. It is used by GStreamer WebRTC pipelines.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

There is no complete mitigation for this vulnerability. The following measures can reduce risk:

1. If WebRTC/DTLS functionality is not required, remove the DTLS plugin shared object from the GStreamer plugins directory (typically /usr/lib64/gstreamer-1.0/libgstdtls.so).
2. Restrict network access to WebRTC/DTLS endpoints to trusted peers only via firewall rules.
3. Deploy GStreamer WebRTC services behind a reverse proxy or media server that validates DTLS certificates before forwarding.