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CVE-2026-53703 Red Hat CVE debrief

A vulnerability was found in the GStreamer RealMedia demuxer (gst-plugins-ugly). When processing a RealMedia (.rm) file, the demuxer parses MDPR (media properties) chunks to configure audio streams. For audio stream header versions 4 and 5, the parser reads fields such as codec type, packet size, sample rate, channel count, and extra codec data length from fixed offsets within the chunk without first checking that the chunk contains enough data. If a malicious file provides an MDPR chunk that is too small to contain a complete audio stream header, the parser reads beyond the end of the buffer. This can cause the application to crash. In some cases, bytes read past the buffer boundary may be incorporated into stream metadata, which could result in limited information disclosure.

Vendor
Red Hat
Product
Red Hat Enterprise Linux 10
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-15
Original CVE updated
2026-08-05
Advisory published
2026-06-15
Advisory updated
2026-08-05

Who should care

Users of GStreamer RealMedia demuxer (gst-plugins-ugly) should be aware of this vulnerability. Particularly, developers and maintainers of applications that utilize this demuxer for processing RealMedia files should take necessary actions to mitigate the risk.

Technical summary

The vulnerability is caused by the lack of proper bounds checking when parsing MDPR chunks in RealMedia files. Specifically, the parser does not verify if the chunk contains enough data before reading fields for audio stream header versions 4 and 5. This can lead to a buffer overflow, causing the application to crash or potentially disclose limited information.

Defensive priority

HIGH

Recommended defensive actions

  • Update to the latest version of GStreamer RealMedia demuxer (gst-plugins-ugly) that includes the fix for this vulnerability.
  • Avoid processing untrusted RealMedia files until the update is applied.

Evidence notes

The CVE-2026-53703 vulnerability has been documented in various sources, including the official CVE record [cve-org] and the National Vulnerability Database [nvd]. Additional information can be found in Red Hat's security advisory [ref-4] and bugzilla entry [ref-5].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53703 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53703

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-53703 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53703

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.