GStreamer rfbsrc Plugin Heap Buffer Overflow Vulnerability
A heap buffer overflow vulnerability was found in GStreamer's rfbsrc plugin. When a client connects to a malicious RFB/VNC server that advertises a 16bpp framebuffer and sends Hextile-encoded updates, the Hextile background fill path writes 32-bit pixel values into a buffer allocated for 16-bit pixels. This type mismatch causes an out-of-bounds heap write that can lead to denial of service (process crash) and potential memory corruption.
Quick answer
GStreamer Project GStreamer rfbsrc plugin should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- GStreamer rfbsrc plugin versions before the vendor fix for CVE-2026-59691
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
GStreamer rfbsrc plugin is affected by CVE-2026-59691. The issue is memory corruption that can crash applications processing untrusted media/network input: a malicious VNC/RFB server can trigger a heap overwrite through Hextile updates. Patch GStreamer packages wherever the affected plugin is installed or loaded by web, desktop, media, or automation services.
- Inventory servers, containers, desktops, and media services that include GStreamer rfbsrc plugin.
- Update GStreamer packages to the vendor-fixed build for CVE-2026-59691.
- Restart applications and services that load GStreamer plugins so patched libraries are active.
- Disable or remove the affected plugin temporarily if untrusted DTLS, VNC/RFB, or media input cannot be avoided before patching.
- Restrict untrusted network peers and file upload pipelines that can reach applications using the vulnerable plugin.
- Review crash logs, service restarts, and core dumps for signs of attempted exploitation.
- Rebuild container images and redeploy from trusted base images rather than patching only the host.
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Verify the fix
- Confirm package inventory shows the vendor-fixed GStreamer build on every affected host or image.
- Confirm long-running services were restarted after the package update.
- Run a safe regression test for the affected media or network workflow in staging.
- Review logs after patching to confirm crash loops stopped.
- Run a Fixnx scan and verify no public admin or media processing endpoint is unexpectedly exposed.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-59691?
GStreamer Project GStreamer rfbsrc plugin versions listed as affected should be reviewed: GStreamer rfbsrc plugin versions before the vendor fix for CVE-2026-59691.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
Why can this risk appear in multiple categories?
A vulnerability can belong to more than one platform or ecosystem. Fixnx keeps one canonical risk page while also listing it in every relevant category.