CVE-2026-17561: Logsign SIEM Code Injection Vulnerability

CVE-2026-17561 Overview

CVE-2026-17561 is a code injection vulnerability affecting Logsign SIEM, developed by Innotim Software, Telecommunications and Consulting Trade Ltd. Co. The flaw allows remote attackers to inject and execute arbitrary code without authentication or user interaction. The issue affects all Logsign SIEM releases prior to version 6.4.108. The vulnerability maps to CWE-94: Improper Control of Generation of Code and carries network-based exploitability with confidentiality, integrity, and availability impact.

Critical Impact
Unauthenticated attackers can execute arbitrary code on Logsign SIEM instances, compromising the security monitoring platform itself and any log data it retains.

Affected Products

Logsign SIEM versions before 6.4.108
Innotim Software, Telecommunications and Consulting Trade Ltd. Co. Logsign SIEM
On-premises Logsign SIEM deployments exposed to untrusted networks

Discovery Timeline

2026-07-31 - CVE-2026-17561 published to NVD
2026-07-31 - Last updated in NVD database

Technical Details for CVE-2026-17561

Vulnerability Analysis

The vulnerability stems from improper control over code generation within Logsign SIEM. Attacker-controlled input reaches a code evaluation or interpretation context without adequate sanitization. This lets an unauthenticated remote actor supply payloads that the application parses and executes as code. Because Logsign SIEM aggregates security telemetry from across an enterprise, exploitation grants access to sensitive log data, alert configurations, and integrations with downstream tools.

Root Cause

The root cause is classified as CWE-94: Improper Control of Generation of Code. The affected component constructs or evaluates code using externally supplied data without enforcing strict input validation or sandboxing. This design flaw permits injected instructions to be executed in the context of the SIEM process.

Attack Vector

Exploitation occurs over the network with no privileges and no user interaction. An attacker who can reach the Logsign SIEM web or API interface can send a crafted request containing malicious code fragments. The interpreter within the application processes the payload, resulting in arbitrary code execution on the host. No verified proof-of-concept code is publicly available. Refer to the Siber Güvenlik Notification TR-26-0717 for vendor-coordinated details.

Detection Methods for CVE-2026-17561

Indicators of Compromise

Unexpected child processes spawned by the Logsign SIEM application user or service account
Outbound network connections from the SIEM host to unfamiliar external IP addresses
New or modified files in Logsign application directories that do not match a known update
Web server or API logs containing payloads with encoded scripting constructs or interpreter directives

Detection Strategies

Inspect HTTP request bodies and query parameters sent to Logsign SIEM endpoints for code-like syntax and encoded payloads
Correlate authentication logs with process creation events on the SIEM host to identify unauthenticated activity followed by execution
Baseline expected process trees for the Logsign service and alert on deviations

Monitoring Recommendations

Enable verbose access logging on the Logsign management interface and forward logs to an independent collector
Monitor egress traffic from the SIEM server, since a compromised SIEM may be leveraged as a pivot point
Track file integrity of Logsign binaries and configuration files with periodic hashing

How to Mitigate CVE-2026-17561

Immediate Actions Required

Upgrade Logsign SIEM to version 6.4.108 or later on all deployments
Restrict network access to Logsign SIEM management interfaces to trusted administrative networks only
Audit recent Logsign SIEM activity for signs of code injection or unauthorized configuration changes
Rotate credentials, API keys, and integration secrets stored within Logsign SIEM after patching

Patch Information

Innotim addresses the issue in Logsign SIEM 6.4.108. Administrators should apply the vendor-supplied update following the guidance in the Siber Güvenlik Notification TR-26-0717. Verify the installed version after the upgrade completes.

Workarounds

Place the Logsign SIEM interface behind a VPN or bastion host until patching is complete
Apply web application firewall rules that block requests containing suspicious code-evaluation syntax targeting Logsign endpoints
Disable or restrict any exposed API endpoints that are not required for operations

bash

# Example: restrict access to the Logsign management port using iptables
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP