CVE-2026-100231

Gstreamer1-plugins-bad-free: gstreamer1-plugins-bad-free: heap out-of-bounds write in asfmux due to incorrect utf-16 size calculation for non-bmp characters

Published Oct 14, 2026 CVSS 3.1 · 6.1 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in the GStreamer multimedia framework's ASF muxer plugin (asfmux). When writing string metadata tags containing Unicode characters outside the Basic Multilingual Plane (such as emoji) to an ASF container, the plugin incorrectly calculates the buffer size needed for the UTF-16LE representation. The size calculation assumes each Unicode code point requires 2 bytes, but non-BMP characters require 4 bytes (surrogate pairs). This leads to a heap out-of-bounds write when the actual UTF-16LE conversion is written into the undersized buffer. An attacker could exploit this by providing media with crafted metadata tags to an application that transcodes or remuxes to ASF format while preserving metadata, potentially causing a denial of service or limited memory corruption.

Remediation

Vendor Workaround

The asfmux plugin can be disabled at build time by passing `-Dgst-plugins-bad:asfmux=disabled` to meson when building GStreamer, or by removing/unloading the `libgstasfmux.so` shared library from the GStreamer plugin directory at runtime. Applications that do not require ASF muxing functionality are not affected. If ASF muxing is required, applications should sanitize metadata tags to remove non-BMP Unicode characters before passing them to the asfmux element.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
cpe:/a:redhat:enterprise_linux:10
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
First Time appeared Red Hat
Red Hat enterprise Linux
Vendors & Products Red Hat
Red Hat enterprise Linux
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A flaw was found in the GStreamer multimedia framework's ASF muxer plugin (asfmux). When writing string metadata tags containing Unicode characters outside the Basic Multilingual Plane (such as emoji) to an ASF container, the plugin incorrectly calculates the buffer size needed for the UTF-16LE representation. The size calculation assumes each Unicode code point requires 2 bytes, but non-BMP characters require 4 bytes (surrogate pairs). This leads to a heap out-of-bounds write when the actual UTF-16LE conversion is written into the undersized buffer. An attacker could exploit this by providing media with crafted metadata tags to an application that transcodes or remuxes to ASF format while preserving metadata, potentially causing a denial of service or limited memory corruption.
Title Gstreamer1-plugins-bad-free: gstreamer1-plugins-bad-free: heap out-of-bounds write in asfmux due to incorrect utf-16 size calculation for non-bmp characters
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-787
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 5, 2026, 4:12 PM
Reserved
Sep 25, 2026, 3:37 PM
Status
Awaiting Analysis
Published
Oct 14, 2026, 10:17 AM
Modified
Nov 5, 2026, 5:17 PM
Severity
Moderate
Public date
Oct 14, 2026, 8:10 AM