CVE-2026-53704 is an out-of-bounds read vulnerability in GStreamer's RealMedia demuxer in the gst-plugins-ugly package. The demuxer improperly parses variable-name and variable-value pairs from the FILEINFO metadata section using re_skip_pascal_string() without validating that offsets remain within the mapped buffer. Additionally, the element count controlling the parsing loop is attacker-controlled and unchecked, potentially causing an infinite loop. A crafted RealMedia file exploiting this flaw can cause application crashes, hangs, or limited adjacent memory reads. Red Hat has released security updates for gstreamer1-plugins-ugly-free in Red Hat Enterprise Linux 9 and 10 to fix this issue.

Successful exploitation can cause denial of service through application crashes or hangs and may allow limited adjacent memory content reads. The CVSS score is 7.1 (High severity) with network attack vector, low attack complexity, no privileges required, user interaction required, and limited confidentiality impact. There is no indication of known exploits in the wild at this time.

Red Hat has released official security updates for gstreamer1-plugins-ugly-free packages in Red Hat Enterprise Linux 9 and 10 to address this vulnerability. Users should apply these updates promptly. For detailed update instructions, refer to Red Hat's advisory and article at https://access.redhat.com/articles/11258. No additional mitigation is indicated by the vendor advisory.