Out-of-Bounds Read in GStreamer RealMedia demuxer (CVE-2026-53703)
Summary
Vulnerability in GStreamer RealMedia demuxer (CVE-2026-53703). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-53703 has been found in GStreamer RealMedia demuxer.
Risk of unauthorized operations or information disclosure. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "GStreamer RealMedia demuxer CVE-2026-53703" on the vendor's site.
CVE-2026-53703 (GStreamer RealMedia demuxer) — CWE-125 / CVSS v3 7.1
Attack vector: remote (network-reachable) / unauthenticated
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in GStreamer RealMedia demuxer.
Check the vendor advisory for the affected versions of GStreamer RealMedia demuxer.
Severity: High (CVSS 7.1/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで GStreamer RealMedia demuxer を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-53703 gst-plugins-ugly1.0
- Ubuntu UBUNTU-CVE-2026-53703 gst-plugins-ugly1.0
References
- web secalert@redhat.com
- web secalert@redhat.com
- web nvd.nist.gov
- web github.com
- web secalert@redhat.com
- web secalert@redhat.com
- web secalert@redhat.com
- web secalert@redhat.com