CVE-2026-86476: GStreamer Buffer Overflow Vulnerability

CVE-2026-86476 Overview

CVE-2026-86476 is a heap buffer overflow vulnerability in the gst-plugins-base component of the GStreamer multimedia framework. The flaw occurs when the library processes video buffers whose attached GstVideoMeta metadata declares plane strides and offsets that exceed the actual backing memory allocation. Because the metadata is not range-checked during deserialization, the video frame mapping code allows consumers to read or write beyond heap boundaries. A local attacker who controls the sending side of a GStreamer inter-process communication (IPC) pipeline can deliver a crafted buffer with fabricated strides to trigger memory corruption in the receiving process. Successful exploitation can cause denial of service or lead to arbitrary code execution within the affected process.

Critical Impact
A local attacker on a GStreamer IPC pipeline can trigger heap memory corruption in the receiving process, enabling denial of service or arbitrary code execution.

Affected Products

GStreamer gst-plugins-base (versions pending vendor disclosure)
Red Hat Enterprise Linux distributions shipping gst-plugins-base
Downstream applications and desktop environments linking against the vulnerable library

Discovery Timeline

2026-10-14 - CVE-2026-86476 published to NVD
2026-10-14 - Last updated in NVD database

Technical Details for CVE-2026-86476

Vulnerability Analysis

The vulnerability resides in how gst-plugins-base handles GstVideoMeta, the metadata structure describing plane layout for video frames. Each plane entry specifies a stride and an offset into the backing memory block. When a buffer arrives over an IPC transport, these values are deserialized directly into memory-mapping routines without validating that the declared geometry fits inside the actual allocation.

When a downstream element calls the video frame mapping API, the library computes read and write positions using attacker-controlled stride and offset values. The resulting pointer arithmetic can address memory far beyond the allocated buffer, producing an out-of-bounds write classified as [CWE-787]. Depending on the surrounding heap layout, this can corrupt adjacent heap chunks, function pointers, or object metadata.

Root Cause

The root cause is missing bounds validation on untrusted GstVideoMeta fields during both metadata deserialization and video frame mapping. The code assumes that stride and offset values accurately reflect the backing buffer, trusting producer-supplied metadata without cross-checking against the allocation size. Any producer able to attach arbitrary metadata to a shared buffer can violate this trust assumption.

Attack Vector

Exploitation requires local access to a GStreamer IPC pipeline, such as a shared-memory transport or socket-based buffer exchange. The attacker controls the sending process and crafts a video buffer with inflated stride or offset values. The receiving process, often running with different or higher privileges, maps the frame and performs the out-of-bounds access. The attack vector is local with low complexity and requires no authentication or user interaction once an IPC channel exists.

No verified proof-of-concept code is publicly available. Technical details are tracked in the Red Hat CVE Details and the Red Hat Bug Report #2529510.

Detection Methods for CVE-2026-86476

Indicators of Compromise

Unexpected crashes, aborts, or SIGSEGV signals in processes that consume GStreamer IPC video buffers
Heap corruption diagnostics (malloc assertions, glibc free(): invalid pointer) emitted by multimedia-related services
Anomalous child-process spawns or shell invocations originating from media playback or screen-sharing daemons

Detection Strategies

Enable AddressSanitizer or Valgrind in test environments to surface out-of-bounds writes from gst_video_frame_map call paths
Monitor system logs and coredumpctl records for repeated crashes in binaries linked against libgstvideo
Baseline normal IPC traffic between GStreamer producers and consumers, and alert on unusually large or malformed metadata frames

Monitoring Recommendations

Track process behavior for media and conferencing applications using endpoint telemetry, focusing on unexpected memory faults and privilege transitions
Correlate crash events with recent IPC connections from untrusted or newly spawned local processes
Audit which local accounts and sandboxed applications can open GStreamer shared-memory or socket endpoints

How to Mitigate CVE-2026-86476

Immediate Actions Required

Inventory all systems with gst-plugins-base installed, including desktop workstations and media server infrastructure
Apply vendor security updates as soon as patched packages are published by Red Hat and upstream GStreamer maintainers
Restrict local access to GStreamer IPC endpoints to trusted users and sandboxed applications only

Patch Information

At the time of publication, patched package versions are tracked in the Red Hat CVE Details page and the associated Red Hat Bug Report #2529510. Administrators should apply distribution updates once released and rebuild downstream applications that statically link affected code.

Workarounds

Disable or remove GStreamer IPC transports (shared memory, shmsrc/shmsink) in pipelines that do not require them
Run media processing services under restrictive sandboxes such as seccomp, AppArmor, or SELinux confinement to limit the blast radius of memory corruption
Avoid exposing GStreamer consumers to buffers originating from untrusted local processes until patches are deployed

bash

# Example: list installed gst-plugins-base packages and their versions
rpm -qa | grep -i gstreamer1-plugins-base

# Example: apply vendor updates once patched packages are available
sudo dnf update gstreamer1-plugins-base