CVE-2026-1961: Forman: foreman: remote code execution via command injection in websocket proxy

Summary: A critical command injection vulnerability exists in Foreman's WebSocket proxy implementation (lib/wsproxy.rb). The vulnerability occurs when constructing shell commands using unsanitized hostname values from compute resource providers. An attacker operating a malicious compute resource server (VMware vSphere, Libvirt, etc.) can achieve remote code execution on the Foreman server when an administrator accesses VM console functionality.

Requirements to exploit: An attacker needs to operate a malicious compute resource server (such as a fake vSphere server) that returns poisoned hostname values. The Foreman administrator must then configure this malicious server as a compute resource and attempt to access the VM console through the normal workflow.

Component affected: foreman

Version affected: Foreman <= 3.17.0 (confirmed), likely all versions from the past 4+ years (wsproxy.rb unchanged since 2020)

Patch available: Yes (need to be reviewed and verified)

Line 44 - Sanitize host parameter safehost = Shellwords.escape(host) Use array form to prevent shell injection cmdarray = [ 'websockify', '--daemon', "--idle-timeout=#{idletimeout}", "--timeout=#{timeout}", port.tos, "#{safehost}:#{hostport}" ] Add SSL options cmdarray += ['--ssl-target'] if ssltarget if Setting[:websocketsencrypt] cmdarray += ['--cert', Setting[:websocketssslcert]] if Setting[:websocketssslcert] cmdarray += ['--key', Setting[:websocketssslkey]] if Setting[:websocketssslkey] end Execute without shell interpretation Open3.popen3(cmdarray) do |stdin, stdout, stderr| # ... existing error handling End Version fixed (if any already): N/A

CVSS: Proposed by reporter - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (Base Score: 8.8 High)

My understanding of the situation (6.8 Medium/High; Still serious, but not "internet critical" – CVSS:3.1/AV:A/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:H) Impact (optional): This vulnerability allows remote code execution as the foreman user, providing direct access to Foreman's database credentials and encryption keys. This enables decryption of all stored infrastructure credentials (vCenter, AWS, SSH keys, API tokens), allowing the attacker to pivot and compromise the entire managed infrastructure. Based on Red Hat's classification, this would be considered Critical impact due to the potential for complete infrastructure compromise. Embargo needed: Yes Reason: Given it is command injection Public date: Need to set default 90-days. There is no date received from the reporter.

Acknowledgement: Houssam Sahli

Steps to reproduce if available: 1. Start malicious vSphere server (attacker system): python3 maliciousvsphereserver.py 2. Configure Foreman compute resource (Foreman UI): - Navigate to: Infrastructure → Compute Resources → Create Compute Resource - Provider: VMware - VCenter/Server: <attackerip> (malicious server address) - Username: user - Password: pass - Load Datacenters (it will load EvilDatacenter) - Display Type: VNC - Uncheck "VNC Console Passwords" and "Enable Caching" - Click "Submit" 3. Trigger exploitation: - Navigate to Virtual Machines tab - Locate "TestVM" in the list - Click Actions → Console 4. Verify RCE (Foreman server): find /tmp -name "vsphererce.txt" 2>/dev/null cat /tmp/systemd-private-/tmp/vsphererce.txt Expected output: foreman

— Red Hat