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Vulnerability · Published Oct 14, 2026 · Assigned by redhat

CVE-2026-100231Gstreamer1-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

Medium 6.1

In plain English

A medium-severity out-of-bounds write in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities).

Severity (CVSS 3.1)6.1Medium
Exploit odds (30 days)0.1%top 96.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12gst-plugins-bad1.0no fix listedDEBIAN-CVE-2026-100231
Debian:13gst-plugins-bad1.0no fix listedDEBIAN-CVE-2026-100231
Debian:14gst-plugins-bad1.0no fix listedDEBIAN-CVE-2026-100231
Ubuntu:26.04:LTSgst-plugins-bad1.0no fix listedUBUNTU-CVE-2026-100231
Ubuntu:26.10gst-plugins-bad1.0no fix listedUBUNTU-CVE-2026-100231

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references

Weakness: CWE-787 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H

References