CVE-2025-23406 Overview
CVE-2025-23406 is an out-of-bounds read vulnerability in Cente middleware TCP/IP Network Series. The flaw stems from improper validation of TCP Maximum Segment Size (MSS) option values during packet processing. A remote attacker can send a specially crafted TCP packet to trigger the out-of-bounds read, causing the affected product to crash. The issue is classified under CWE-125: Out-of-bounds Read and affects the availability of embedded systems that rely on this networking stack.
Critical Impact
Remote, unauthenticated attackers can crash affected devices by sending crafted TCP packets, disrupting availability of embedded systems and IoT devices relying on Cente TCP/IP middleware.
Affected Products
- Cente middleware TCP/IP Network Series
- Embedded devices integrating the affected Cente TCP/IP stack
- Products from vendors bundling Cente middleware components
Discovery Timeline
- 2025-02-14 - CVE-2025-23406 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-23406
Vulnerability Analysis
The vulnerability resides in the TCP option parsing logic of the Cente TCP/IP middleware. When the stack processes an incoming TCP segment, it inspects TCP options including the Maximum Segment Size (MSS) option. The affected code fails to properly validate the MSS option value or its length field before reading associated memory. A malformed MSS option causes the parser to read memory outside the bounds of the intended buffer.
The out-of-bounds read produces undefined behavior in the affected process. In embedded contexts, this typically manifests as a system crash that halts network services or the entire device. Recovery generally requires a manual reboot or watchdog-triggered reset.
Root Cause
The root cause is missing bounds checking on TCP MSS option values, mapped to CWE-125: Out-of-bounds Read. The parser trusts option length and value fields supplied by the remote peer without validating that they fall within the segment or expected ranges. This omission allows attacker-controlled inputs to steer memory reads beyond allocated buffer boundaries.
Attack Vector
Exploitation requires only network access to the affected device. No authentication, user interaction, or elevated privileges are needed. An attacker crafts a TCP packet containing a malformed MSS option, typically within the SYN or SYN-ACK handshake where MSS negotiation occurs. Upon receiving and parsing the packet, the affected stack triggers the out-of-bounds read and crashes.
Detailed technical information is available in the JVN Vulnerability Report and the CENTE Obstacle Overview.
Detection Methods for CVE-2025-23406
Indicators of Compromise
- Unexpected reboots or crash logs on embedded devices running Cente TCP/IP middleware following inbound TCP connection attempts
- Loss of network connectivity to affected devices coinciding with anomalous inbound TCP SYN traffic
- Watchdog reset events correlated with TCP handshake activity from untrusted sources
Detection Strategies
- Inspect inbound TCP traffic for malformed MSS option lengths or values that exceed protocol expectations
- Deploy network intrusion detection signatures that flag TCP options with invalid length fields or truncated option data
- Correlate device crash events with packet capture data at network chokepoints to identify malicious senders
Monitoring Recommendations
- Enable syslog forwarding from embedded devices to a centralized log platform to capture crash and reboot events
- Monitor availability metrics for devices using Cente middleware and alert on repeated unexpected outages
- Baseline normal TCP option patterns on operational network segments and alert on deviations
How to Mitigate CVE-2025-23406
Immediate Actions Required
- Identify all devices and products that embed the Cente TCP/IP Network Series middleware in the environment
- Restrict network exposure of affected devices using firewall rules and network segmentation
- Contact device vendors to determine patch availability for products bundling the affected middleware
Patch Information
Refer to the CENTE Obstacle Overview and the JVN Vulnerability Report for vendor guidance and fixed versions. Because Cente middleware is redistributed within third-party embedded products, patches are typically delivered through downstream device vendors rather than directly by end users.
Workarounds
- Place affected devices behind a firewall or gateway that filters malformed TCP option fields before packets reach the vulnerable stack
- Limit inbound TCP connections to trusted source addresses using access control lists on upstream network equipment
- Deploy an inline device that normalizes TCP options and drops packets with invalid MSS option lengths
- Enable watchdog-based automatic recovery on affected devices to reduce downtime from crash-induced outages
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
