CVE-2025-43971 in GoBGP
Summary
by MITRE • 04/21/2025
An issue was discovered in GoBGP before 3.35.0. pkg/packet/bgp/bgp.go allows attackers to cause a panic via a zero value for softwareVersionLen.
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Analysis
by VulDB Data Team • 07/23/2025
The vulnerability identified as CVE-2025-43971 represents a critical denial of service weakness in GoBGP versions prior to 3.35.0. This issue manifests within the packet processing module specifically in the file pkg/packet/bgp/bgp.go where the software fails to properly validate incoming BGP packet structures. The flaw occurs when an attacker crafts a malicious BGP packet containing a zero value for the softwareVersionLen field, which triggers an unexpected panic condition in the routing protocol implementation. This particular vulnerability falls under the category of improper input validation and can be classified as CWE-20, indicating improper input validation within the software architecture. The affected component processes BGP (Border Gateway Protocol) packets which are fundamental to internet routing operations, making this a significant concern for network infrastructure security.
The technical execution of this vulnerability requires an attacker to construct and transmit a specially crafted BGP packet that includes a softwareVersionLen field set to zero. When GoBGP processes this malformed packet, the software encounters a nil pointer dereference or division by zero condition that causes the application to crash and terminate unexpectedly. This panic condition disrupts the normal operation of the BGP routing process and can lead to complete service interruption for the affected network node. The vulnerability is particularly dangerous because BGP is a critical protocol for internet routing, and any disruption can cause cascading failures across interconnected networks. The attack vector is remote and requires no authentication, making it easily exploitable by malicious actors who can simply send the malformed packet to any vulnerable GoBGP instance.
The operational impact of CVE-2025-43971 extends beyond simple service disruption to potentially compromise network stability and availability. When a GoBGP instance panics and restarts, it can cause routing table inconsistencies, temporary loss of connectivity, and disruption of BGP sessions with neighboring routers. Network operators may experience significant downtime as the system recovers from the crash, and in large-scale deployments, this could affect thousands of routes and cause widespread connectivity issues. The vulnerability aligns with ATT&CK technique T1499.004 which involves network denial of service attacks, specifically targeting network infrastructure components. Organizations using GoBGP for routing operations face the risk of unauthorized parties causing deliberate service interruptions that could be used for competitive advantage or to disrupt network operations. The panic condition can also be leveraged in combination with other attacks to create more sophisticated disruption campaigns.
Mitigation strategies for this vulnerability require immediate patching of all affected GoBGP installations to version 3.35.0 or later where the input validation has been properly implemented. Network administrators should also implement monitoring solutions to detect unusual BGP packet patterns and potential exploitation attempts. The fix involves adding proper validation checks for the softwareVersionLen field to ensure it cannot be zero or negative values before processing the BGP packet. Additional defensive measures include implementing BGP packet filtering at network boundaries to drop malformed packets before they reach the GoBGP instance, and deploying intrusion detection systems that can identify and alert on suspicious BGP traffic patterns. Organizations should also consider implementing redundant BGP routing configurations to minimize the impact of any single point of failure. The vulnerability highlights the importance of proper input validation in network protocol implementations and serves as a reminder of the critical nature of security updates in routing software.