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Vulnerabilities

Vulnerability · CVE-2026-100231

A flaw was found in the GStreamer multimedia framework's ASF muxer plugin (asfmux).

Published Oct 14, 2026 · catalog updated Oct 15, 2026 · A flaw was found

Check if you run it

No confirmed exploitation is on record for CVE-2026-100231. EPSS is 0.15%. Act only if a listed version of A flaw was found is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A flaw was found).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.15%
Remediation
Advisory link
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-100231

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-100231. EPSS is 0.15%. Act only if a listed version of A flaw was found is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-787: Out-of-bounds Write. EPSS 0.15%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 14, 2026 · NIST NVD

    Detected

    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 chara

  2. Oct 15, 2026 · NIST NVD

    Updated

    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 chara

Sources

  • CVE.orgVulnerability recordCVE-2026-100231

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-100231

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-100231

    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 f

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.