CVE-2026-27561 Overview
CVE-2026-27561 is a command injection vulnerability [CWE-78] affecting the /api/iodd/config endpoint of an industrial device covered by CERT-VDE advisories. An authenticated remote attacker holding administrative credentials can send a crafted HTTP GET request that injects operating system commands. The injected commands execute with root privileges on the underlying device. The flaw was disclosed through CERT-VDE advisories VDE-2026-014, VDE-2026-027, and VDE-2026-028. The vulnerability requires high privileges but no user interaction and is exploitable over the network.
Critical Impact
Successful exploitation grants root-level command execution on the affected device, enabling full compromise of confidentiality, integrity, and availability.
Affected Products
- Products covered by CERT-VDE advisory VDE-2026-014
- Products covered by CERT-VDE advisory VDE-2026-027
- Products covered by CERT-VDE advisory VDE-2026-028
Discovery Timeline
- 2026-09-16 - CVE-2026-27561 published to NVD
- 2026-09-16 - Last updated in NVD database
Technical Details for CVE-2026-27561
Vulnerability Analysis
The /api/iodd/config endpoint accepts parameters that are passed to an underlying operating system shell without sanitization. An attacker authenticated as admin sends a crafted GET request whose parameter values contain shell metacharacters. The device concatenates those values into a command string and executes the result. Because the web service runs as root, the injected commands inherit root privileges. The attacker gains arbitrary control of the device operating system, including file system access, network configuration, and process control. The Exploit Prediction Scoring System (EPSS) places this issue in the upper percentile of vulnerabilities based on observed characteristics.
Root Cause
The root cause is improper neutralization of special elements used in an operating system command [CWE-78]. The /api/iodd/config handler builds a shell command by concatenating attacker-controlled input rather than passing arguments through a safe execution API. Input validation and metacharacter escaping are absent for the affected parameters.
Attack Vector
The attack vector is network-based and requires valid administrator credentials. An attacker with admin access issues an HTTP GET request to /api/iodd/config containing shell metacharacters such as ;, |, `, or $() in a vulnerable parameter. The device parses the request, invokes a shell, and runs the injected payload as root. Exploitation does not require user interaction. Prerequisite credential access can be obtained through phishing, credential stuffing, or insider abuse. See the CERT-VDE advisories for parameter-level details.
See the CERT-VDE Advisory VDE-2026-014, CERT-VDE Advisory VDE-2026-027, and CERT-VDE Advisory VDE-2026-028 for technical specifics.
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Stop Exploit AttemptsDetection Methods for CVE-2026-27561
Indicators of Compromise
- HTTP GET requests to /api/iodd/config containing shell metacharacters such as ;, &&, |, backticks, or $() in query parameters.
- Unexpected root-owned child processes spawned by the web service handling the /api/iodd/config endpoint.
- Outbound network connections initiated from the device shortly after administrative API calls.
- New or modified system files, cron entries, or startup scripts on the device following admin API activity.
Detection Strategies
- Inspect web server and reverse proxy logs for requests to /api/iodd/config that contain URL-encoded shell metacharacters.
- Alert on process lineage where the device web service spawns /bin/sh, /bin/bash, wget, curl, nc, or similar utilities.
- Correlate administrator authentication events with subsequent process execution telemetry to identify credential misuse.
Monitoring Recommendations
- Capture and centralize HTTP access logs from the device management interface for retention and analysis.
- Monitor administrator account usage patterns and flag logins from atypical source IP addresses or times.
- Baseline normal process behavior of the device and alert on deviations following API activity.
How to Mitigate CVE-2026-27561
Immediate Actions Required
- Apply the fixed firmware referenced in CERT-VDE advisories VDE-2026-014, VDE-2026-027, and VDE-2026-028 as soon as they are available.
- Restrict network access to the device management interface using firewall rules or network segmentation.
- Rotate administrator credentials and enforce strong, unique passwords for all admin accounts.
- Audit administrator account activity for signs of prior misuse of the /api/iodd/config endpoint.
Patch Information
Refer to the vendor coordination pages for patched firmware versions: CERT-VDE Advisory VDE-2026-014, CERT-VDE Advisory VDE-2026-027, and CERT-VDE Advisory VDE-2026-028. Deploy the vendor-supplied firmware update to eliminate the injection path in the /api/iodd/config handler.
Workarounds
- Place the device behind a management VLAN reachable only from an administrative jump host.
- Disable or block external access to the /api/iodd/config endpoint at the network perimeter when the function is not in active use.
- Enforce multi-factor authentication for administrative access at the network layer where the device does not natively support it.
# Configuration example: restrict access to the device management interface
# Replace <MGMT_IP> and <ADMIN_SUBNET> with values for your environment
iptables -A INPUT -p tcp -s <ADMIN_SUBNET> -d <MGMT_IP> --dport 443 -j ACCEPT
iptables -A INPUT -p tcp -d <MGMT_IP> --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
