CVE-2023-3107 in FreeBSD
Summary
by MITRE • 08/02/2023
A set of carefully crafted ipv6 packets can trigger an integer overflow in the calculation of a fragment reassembled packet's payload length field. This allows an attacker to trigger a kernel panic, resulting in a denial of service.
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Analysis
by VulDB Data Team • 07/09/2025
This vulnerability represents a critical integer overflow condition within the ipv6 fragment reassembly mechanism of the linux kernel. The flaw occurs when processing fragmented ipv6 packets where an attacker crafts malicious packet sequences that cause arithmetic overflow during the calculation of the reassembled packet's payload length field. The vulnerability resides in the kernel's ipv6 fragmentation handling code which fails to properly validate the arithmetic operations involved in determining the final packet size during reassembly. This type of vulnerability falls under the category of integer overflow as defined by cwe-190 and represents a specific instance of improper integer handling in kernel space operations. The issue is particularly dangerous because it can be exploited through network-based attacks without requiring any special privileges or authentication.
The operational impact of this vulnerability extends beyond simple denial of service to potentially compromising system stability and availability. When an attacker successfully triggers the integer overflow condition, the kernel's ipv6 reassembly logic encounters an arithmetic error that leads to a kernel panic, causing the entire system to become unresponsive and requiring manual reboot. This creates a significant risk for network infrastructure devices, servers, and any systems that process ipv6 traffic, as the attack can be executed remotely and does not require local access. The vulnerability affects systems running linux kernels that implement ipv6 fragmentation handling, making it particularly concerning for network services, routers, and any device that must process fragmented ipv6 packets. The attack vector is network-based, allowing remote exploitation through carefully crafted ipv6 packet sequences that manipulate the fragment offset and length fields in ways that trigger the overflow condition.
From a cybersecurity perspective, this vulnerability aligns with several tactics described in the attack mitigation framework, particularly those involving denial of service attacks and kernel-level exploitation techniques. The vulnerability demonstrates how seemingly benign network protocols can become attack vectors when implementation flaws exist in core kernel components. The integer overflow in kernel space represents a classic security weakness that can potentially be escalated to more serious exploits if additional vulnerabilities exist in the same code paths. Security professionals should note that this vulnerability is particularly concerning for systems that rely heavily on ipv6 connectivity and may be exploited by attackers seeking to disrupt network services or cause system downtime. The exploitability is relatively straightforward since it only requires sending specific ipv6 packets to the target system, making it a viable attack method for network-based disruption campaigns.
Mitigation strategies for this vulnerability should focus on immediate kernel updates and patches provided by linux kernel maintainers and operating system vendors. Organizations should prioritize patching their systems to address the specific integer overflow condition in the ipv6 fragment reassembly code. Network administrators can implement temporary mitigation measures such as disabling ipv6 fragmentation processing or filtering ipv6 fragments at network boundaries, though these approaches may impact legitimate network functionality. The vulnerability highlights the importance of proper input validation and arithmetic overflow checking in kernel code, particularly in network protocol handling components. System monitoring should include detection of unusual ipv6 packet patterns that might indicate exploitation attempts, and incident response procedures should account for potential kernel panics as a result of this vulnerability. Regular security assessments of kernel components and network protocol implementations should be conducted to identify similar integer overflow conditions that could lead to system instability or privilege escalation.