CVE-2026-30364: CentSDR Buffer Overflow Vulnerability

CVE-2026-30364 Overview

CVE-2026-30364 is a stack overflow vulnerability discovered in CentSDR, an open-source software-defined radio project. The vulnerability exists in the Thread1 function within commit e40795 of the CentSDR codebase. This memory corruption flaw can be exploited remotely without requiring authentication, potentially leading to denial of service conditions.

Critical Impact

Remote attackers can trigger a stack overflow in the Thread1 function, causing application crashes and denial of service without requiring any user interaction or authentication.

Affected Products

• CentSDR commit e40795 and potentially earlier versions
• CentSDR builds derived from the affected commit

Discovery Timeline

• 2026-04-15 - CVE-2026-30364 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2026-30364

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow). The flaw resides in the Thread1 function where improper boundary checking allows data to overflow the allocated stack buffer. The network-accessible nature of this vulnerability means attackers can potentially trigger the overflow remotely without needing local access to the system.

The vulnerability can be exploited with low attack complexity, requiring no privileges or user interaction. While the integrity and confidentiality impact is limited, the availability impact is significant, allowing attackers to crash the application or cause denial of service conditions.

Root Cause

The root cause of this vulnerability is insufficient bounds checking in the Thread1 function. When processing input data, the function fails to properly validate the size of incoming data against the allocated stack buffer, allowing an attacker to write beyond the buffer boundaries and corrupt adjacent stack memory.

Stack-based buffer overflows occur when a program writes more data to a buffer on the stack than it can hold. In the context of the Thread1 function, this can lead to corruption of return addresses, saved registers, and other critical stack data structures.

Attack Vector

The attack vector for CVE-2026-30364 is network-based. An attacker can remotely send specially crafted input to the affected CentSDR instance to trigger the stack overflow condition. The vulnerability does not require any privileges or user interaction to exploit, making it particularly dangerous for exposed systems.

The exploitation mechanism involves sending oversized or malformed data that the Thread1 function processes without adequate size validation. Technical details and proof-of-concept information are available in the GitHub Issue Discussion and the GitHub Gist PoC Repository.

Detection Methods for CVE-2026-30364

Indicators of Compromise

• Unexpected application crashes or service interruptions in CentSDR processes
• Abnormal memory usage patterns or stack corruption errors in application logs
• Network traffic containing unusually large or malformed payloads targeting CentSDR services
• Core dumps or crash reports indicating stack overflow conditions in the Thread1 function

Detection Strategies

• Deploy network intrusion detection systems (IDS) to monitor for anomalous traffic patterns targeting CentSDR services
• Implement application-level logging to capture and alert on crash events related to the Thread1 function
• Use memory protection tools and stack canaries to detect overflow attempts at runtime
• Monitor system logs for segmentation faults or stack smashing detected messages

Monitoring Recommendations

• Configure real-time alerting for CentSDR process crashes or unexpected restarts
• Implement network traffic analysis to identify potential exploitation attempts
• Enable verbose logging on CentSDR instances to capture detailed error information
• Consider deploying endpoint detection and response (EDR) solutions to monitor for exploitation behavior

How to Mitigate CVE-2026-30364

Immediate Actions Required

• Update CentSDR to a version that includes the fix for the stack overflow in the Thread1 function
• Restrict network access to CentSDR instances to trusted sources only
• Implement network segmentation to limit exposure of vulnerable systems
• Monitor affected systems closely for signs of exploitation attempts

Patch Information

Users should monitor the official CentSDR GitHub repository for patches addressing this vulnerability. The GitHub Issue Discussion may contain updates regarding the fix status. As this is an open-source project, users should review commits after e40795 for security patches or apply community-contributed fixes.

Workarounds

• Implement firewall rules to restrict network access to CentSDR services from untrusted networks
• Deploy a reverse proxy or web application firewall (WAF) to filter malicious input before it reaches the application
• Consider running CentSDR in a sandboxed environment to limit the impact of potential exploitation
• If possible, disable or restrict the functionality associated with the Thread1 function until a patch is available

# Example firewall rule to restrict access to CentSDR
# Adjust port number based on your CentSDR configuration
iptables -A INPUT -p tcp --dport <centsdr_port> -s <trusted_network> -j ACCEPT
iptables -A INPUT -p tcp --dport <centsdr_port> -j DROP