CVE-2026-38713 Overview
CVE-2026-38713 is a command injection vulnerability [CWE-77] affecting multiple Cudy router firmware versions. The flaw resides in the ipsec_conn interface, which fails to sanitize user-supplied input before passing it to a system shell. Remote attackers can execute arbitrary commands with root privileges through crafted requests. The issue impacts a broad range of Cudy TR and WR series routers running the affected firmware releases. Cudy documented the flaw in security advisory SA-26-7. The EPSS score of 2.619% (83.964 percentile) indicates elevated exploit likelihood relative to the general CVE population.
Critical Impact
Unauthenticated network attackers can execute arbitrary shell commands as root on affected Cudy routers, resulting in full device compromise.
Affected Products
- Cudy TR1200 v2.4.15 and TR3000 v2.4.21
- Cudy WR300 v2.4.25, WR1200 v2.4.23, WR1300 v2.4.22, WR1500 v2.3.10
- Cudy WR3000 v2.4.19, WR3600 v2.3.16, and WR6500 v2.3.15
Discovery Timeline
- 2026-07-31 - CVE-2026-38713 published to NVD
- 2026-08-03 - Last updated in NVD database
Technical Details for CVE-2026-38713
Vulnerability Analysis
The vulnerability resides in the ipsec_conn interface exposed by Cudy router firmware. The interface manages IPsec connection parameters received from the router's administrative surface. User-controlled fields flow into shell command construction without adequate neutralization of shell metacharacters. An attacker who submits crafted input can break out of the intended argument context and append arbitrary commands. The router executes those commands under the root account, granting complete control over the device. This class of weakness is tracked as Improper Neutralization of Special Elements used in a Command [CWE-77].
Root Cause
The root cause is unsafe construction of operating system commands from external input in the ipsec_conn handler. The firmware concatenates request parameters into shell invocations without escaping characters such as ;, |, &, `, or $(). Cudy has addressed the flaw in firmware updates referenced in advisory SA-26-7.
Attack Vector
Exploitation requires network reachability to the affected router's management interface. According to the CVSS vector, no authentication or user interaction is needed. An attacker sends a crafted request to the ipsec_conn endpoint containing shell metacharacters embedded in a controllable parameter. The firmware processes the request, invokes the shell, and executes the injected commands as root. Post-exploitation actions include persistent implants, credential theft from configuration files, DNS hijacking, and pivoting into internal networks.
Verified proof-of-concept code is not publicly linked in the advisory. See the Cudy Security Advisory SA-26-7 for vendor technical details.
Detection Methods for CVE-2026-38713
Indicators of Compromise
- Unexpected outbound connections from router management IPs to unfamiliar hosts, indicating implant beaconing.
- Presence of shell metacharacters (;, |, `, $()) in HTTP request logs targeting the ipsec_conn endpoint.
- Unauthorized modifications to router configuration files, DNS settings, or firewall rules.
- New or unknown processes running as root on the router that do not correspond to vendor firmware components.
Detection Strategies
- Inspect web server and management logs on the router for POST or GET requests to IPsec configuration endpoints containing suspicious characters.
- Monitor upstream firewall and NetFlow data for anomalous traffic originating from router IP addresses.
- Compare running firmware versions against the affected list and flag any device that has not been updated.
Monitoring Recommendations
- Forward router syslog to a centralized SIEM and alert on configuration changes to IPsec parameters.
- Baseline outbound DNS and HTTP traffic from network infrastructure devices and alert on deviations.
- Perform periodic integrity checks of router firmware and configuration snapshots.
How to Mitigate CVE-2026-38713
Immediate Actions Required
- Apply the firmware updates published by Cudy in advisory SA-26-7 for each affected model.
- Restrict access to router administrative interfaces to trusted management networks only.
- Disable remote WAN-side administration if it is not required for operations.
- Rotate administrative credentials and preshared keys after patching, in case of prior compromise.
Patch Information
Cudy has released firmware updates addressing the command injection in the ipsec_conn interface. Refer to the Cudy Security Advisory SA-26-7 for the specific fixed firmware versions corresponding to each affected model.
Workarounds
- Block external access to the router management interface at the perimeter until firmware is applied.
- Place vulnerable routers behind a segmented management VLAN with strict ACLs.
- Disable the IPsec feature on affected devices if it is not in active use, reducing exposure of the vulnerable handler.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
