CVE-2026-51082: Proxmox Virtual Environment race condition in VNC session handling

CVE-2026-51082 · Severity: info · Published 2026-07-17

A security flaw in Proxmox Virtual Environment (PVE) allows a user with limited administrative permissions to hijack the remote console session of a different virtual machine. This occurs when two users attempt to access consoles at the same time, potentially allowing an attacker to view or control a server they are not authorized to access. This could lead to the exposure of sensitive data or unauthorized changes to critical business systems.

Vendors: Proxmox.

Quick answers

Is CVE-2026-51082 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-51082 being exploited in the wild.
How severe is CVE-2026-51082?
Informational severity, published 17 July 2026.
Which products and versions are affected?
Proxmox PVE Container 6.1.x before 6.1.3, 5.3.x before 5.3.4; Proxmox PVE Manager 9.1.x before 9.1.9, 8.4.x before 8.4.19; Proxmox QEMU Server 9.1.x before 9.1.7, 8.4.x before 8.4.7.
Is there a fix for CVE-2026-51082?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-51082 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-51082?
Check whether you run Proxmox PVE Container, Proxmox PVE Manager or Proxmox QEMU Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A race condition exists between the 'vncproxy' and 'vncwebsocket' API calls in multiple Proxmox VE components, including pve-manager, qemu-server, and pve-container. An attacker who possesses the privileges required to initiate a 'vncproxy' call can exploit this timing window to intercept and hijack a VNC session being established simultaneously by a different legitimate user for a different VM or container. This allows for unauthorized access to the guest console. The issue is resolved in pve-manager 9.1.9/8.4.19, qemu-server 9.1.7/8.4.7, and pve-container 6.1.3/5.3.4.

Affected products

  • Proxmox pve-manager 9.1.x before 9.1.9, 8.4.x before 8.4.19
  • Proxmox qemu-server 9.1.x before 9.1.7, 8.4.x before 8.4.7
  • Proxmox pve-container 6.1.x before 6.1.3, 5.3.x before 5.3.4

Timeline

  • 2026-07-17: disclosed
  • 2026-07-17: advisory

References

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