Red Hat Enterprise Linux ASF muxer plugin out-of-bounds write

Summaryinfo

A vulnerability was found in Red Hat Enterprise Linux. It has been rated as problematic. Affected by this issue is some unknown functionality of the component ASF muxer plugin. The manipulation leads to out-of-bounds write. This vulnerability is listed as CVE-2026-100231. The attack must be carried out locally. There is no available exploit.

Detailsinfo

A vulnerability was found in Red Hat Enterprise Linux (version unknown) and classified as problematic. This issue affects an unknown function of the component ASF muxer plugin. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at access.redhat.com. The identification of this vulnerability is CVE-2026-100231 since 09/25/2026. The exploitation is known to be easy. Attacking locally is a requirement. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/14/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Operating System

Vendor

• Red Hat

Name

• Enterprise Linux

License

• commercial

Website

• Vendor: https://www.redhat.com/

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