---
id: CVE-2026-100231
title: >-
  A flaw was found in the GStreamer multimedia framework's ASF muxer plugin
  (asfmux)
summary: >-
  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 inco…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H'
cwe:
  - CWE-787
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T10:17:50.483'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100231'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-100231'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541468'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100231.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-100231'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100231'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
ingestedAt: '2026-10-14T10:25:41.199Z'
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - enterprise_linux 10
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
---

## Overview

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

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100231.json)