CVE-2023-3022 in Linux
Summary
by MITRE • 06/19/2023
A flaw was found in the IPv6 module of the Linux kernel. The arg.result was not used consistently in fib6_rule_lookup, sometimes holding rt6_info and other times fib6_info. This was not accounted for in other parts of the code where rt6_info was expected unconditionally, potentially leading to a kernel panic in fib6_rule_suppress.
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Analysis
by VulDB Data Team • 01/26/2026
The vulnerability identified as CVE-2023-3022 represents a critical inconsistency within the Linux kernel's IPv6 implementation that could result in system instability and potential denial of service conditions. This flaw resides in the fib6_rule_lookup function within the IPv6 routing subsystem, where improper handling of the arg.result variable creates a dangerous inconsistency in data type expectations throughout the kernel's networking stack. The vulnerability manifests when the arg.result field is populated with different data types during the routing lookup process, specifically alternating between rt6_info and fib6_info structures without proper type checking or conversion mechanisms.
The technical root cause of this vulnerability stems from a lack of proper type consistency in the kernel's IPv6 routing table lookup logic. When fib6_rule_lookup processes routing rules, it assigns different types of routing information to the arg.result field depending on the specific lookup conditions encountered. This inconsistent assignment pattern creates a scenario where subsequent code paths that expect a specific routing information structure type fail to properly handle the alternative data type. The issue particularly impacts the fib6_rule_suppress function which makes unconditional assumptions about the data type stored in arg.result, leading to potential kernel panics when memory access violations occur due to incorrect structure dereferencing.
The operational impact of CVE-2023-3022 extends beyond simple system instability, as it represents a potential attack vector for privilege escalation and system compromise. When a kernel panic occurs due to this inconsistency, the system experiences an abrupt termination that can result in complete service disruption for network-dependent applications and services. This vulnerability affects systems running Linux kernel versions where the IPv6 routing module is active, potentially impacting servers, routers, and any network infrastructure that relies on IPv6 connectivity. The vulnerability's exploitation potential is heightened by the fact that it occurs during normal network routing operations, making it difficult to detect and prevent through standard security monitoring approaches.
This vulnerability aligns with CWE-457: Use of Uninitialized Variable and CWE-121: Stack-based Buffer Overflow in its manifestation pattern, as the inconsistent data handling creates scenarios where memory access violations occur due to improper type assumptions. The issue also maps to ATT&CK technique T1068: Exploitation for Privilege Escalation, as successful exploitation could potentially allow an attacker to gain elevated privileges within the kernel space. Additionally, the vulnerability demonstrates characteristics of T1499.004: Endpoint Denial of Service, where the inconsistent handling of routing information could be leveraged to cause system-wide network service disruption. Organizations should implement immediate mitigations including kernel updates, network segmentation to limit exposure, and monitoring for unusual routing behavior patterns that might indicate exploitation attempts.
The remediation approach for CVE-2023-3022 requires careful attention to kernel version management and patch deployment strategies. System administrators should prioritize updating to patched kernel versions that address the inconsistent data type handling in the IPv6 routing module. The fix typically involves implementing proper type checking and conversion mechanisms within fib6_rule_lookup to ensure consistent assignment of the arg.result field, preventing the scenario where different routing information types are stored in the same variable without proper handling. Organizations should also consider implementing network monitoring solutions that can detect anomalous routing behavior patterns and establish incident response procedures specifically designed to handle kernel panic conditions resulting from such vulnerabilities.