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Heap out-of-bounds write in GStreamer asfmux with non-BMP tags

Priority LOW 26CWE-787Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · Low · High
Fix status
Deferred Red Hat: fix deferred

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

The GStreamer multimedia framework's ASF muxer plugin (asfmux) miscalculates the buffer size for UTF-16LE metadata strings. It assumes each Unicode code point needs 2 bytes, but non-BMP characters need 4 bytes as surrogate pairs, which causes a heap out-of-bounds write (CWE-787). An attacker with local access and user interaction can provide media with crafted metadata tags to an application that transcodes or remuxes to ASF while preserving metadata, which can cause a denial of service or limited memory corruption.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00141 3rd percentileScored 2026-11-07
Fix Deferred Red Hat: fix deferred

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Red HatRed Hat Enterprise Linux 10——No fix listedCNA
Red HatRed Hat Enterprise Linux 7——No fix listedCNA
Red HatRed Hat Enterprise Linux 8——No fix listedCNA
Red HatRed Hat Enterprise Linux 9——No fix listedCNA
  • Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat Enterprise Linux 7 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in — No fix listed CNA

CPE names CNA · 4

CPEVersionsRoleVendor
cpe:/a:redhat:enterprise_linux:1010—Red Hat
cpe:/o:redhat:rhel_els:77—Red Hat
cpe:/a:redhat:enterprise_linux:88—Red Hat
cpe:/a:redhat:enterprise_linux:99—Red Hat
  • cpe:/a:redhat:enterprise_linux:10 Versions 10 — ·Red Hat
  • cpe:/o:redhat:rhel_els:7 Versions 7 — ·Red Hat
  • cpe:/a:redhat:enterprise_linux:8 Versions 8 — ·Red Hat
  • cpe:/a:redhat:enterprise_linux:9 Versions 9 — ·Red Hat

Remediation

The sources list no fixed version for Red Hat Enterprise Linux 10, 7, 8 or 9.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-14 Threatist record created from CVE-2026-100231
  2. 2026-10-14 Alias added: GHSA-qxfv-rjq3-mg7m
  3. 2026-10-14 Priority changed: MEDIUM → LOW
  4. 2026-10-16 CISA SSVC decision points changed
  5. 2026-10-16 Affected versions changed · Red Hat
  6. 2026-10-16 CVSS score added · Red Hat

References

  • TI-2019-15875 Protection mechanism failure in Jenkins Pipeline: Groovy Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-15874 Protection mechanism failure in Jenkins Script Security Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-05363 Code injection in Elastic Kibana KEVCVSS 3.1CRITICAL 10.0
  • TI-2019-03949 Out-of-bounds write in ESXi and Horizon DaaS KEVCVSS 3.1CRITICAL 9.8
  • TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
See all 7413 →

Sources