CVE-2010-1188 in Linux
Summary
by MITRE
Use-after-free vulnerability in net/ipv4/tcp_input.c in the Linux kernel 2.6 before 2.6.20, when IPV6_RECVPKTINFO is set on a listening socket, allows remote attackers to cause a denial of service (kernel panic) via a SYN packet while the socket is in a listening (TCP_LISTEN) state, which is not properly handled and causes the skb structure to be freed.
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Analysis
by VulDB Data Team • 05/04/2026
The vulnerability described in CVE-2010-1188 represents a critical use-after-free condition within the Linux kernel's TCP implementation that specifically affects versions prior to 2.6.20. This flaw exists in the net/ipv4/tcp_input.c file and manifests when the IPV6_RECVPKTINFO socket option is configured on a listening socket, creating a scenario where remote attackers can exploit the kernel's handling of SYN packets during the TCP_LISTEN state. The vulnerability stems from improper memory management where the kernel fails to properly validate socket state transitions, leading to a situation where an skb (socket buffer) structure gets freed while still being referenced by the kernel's TCP processing code.
The technical exploitation of this vulnerability occurs when a remote attacker sends a specially crafted SYN packet to a listening socket that has IPV6_RECVPKTINFO enabled. During the normal TCP connection establishment process, the kernel maintains various socket structures in memory to track connection state and packet information. When the socket is in TCP_LISTEN state and receives a SYN packet, the kernel attempts to process the packet while also handling the IPV6_RECVPKTINFO option, which requires additional packet information to be stored and managed. The flaw arises because the kernel's code path does not adequately check whether the socket state has changed or if the associated skb structure has already been freed during an earlier processing stage, resulting in a use-after-free condition when the freed memory is accessed.
This vulnerability directly impacts system availability and can be leveraged for denial of service attacks that result in kernel panics, effectively crashing the target system and rendering it unavailable to legitimate users. The operational impact extends beyond simple service disruption as the kernel panic can cause complete system instability, potentially requiring manual reboot and recovery procedures that can take significant time to complete. The vulnerability affects systems running Linux kernel versions 2.6.x where x is less than 20, making it particularly concerning for enterprise environments that may have legacy systems or delayed patch management processes. Network services such as web servers, database servers, and other TCP-based applications that utilize listening sockets with IPV6_RECVPKTINFO enabled are at risk, as attackers can trigger the vulnerability without requiring authentication or specialized privileges.
The vulnerability aligns with CWE-416, which describes the use of freed memory condition, and can be mapped to ATT&CK technique T1499.004, which involves network denial of service attacks. Security practitioners should prioritize patching affected systems immediately, as the vulnerability can be exploited remotely without requiring any authentication credentials. The recommended mitigation strategy involves upgrading to Linux kernel version 2.6.20 or later, where the memory management issue has been corrected through proper validation of socket states and skb structure handling. Additionally, system administrators should consider implementing network segmentation and monitoring to detect unusual SYN packet patterns that may indicate exploitation attempts, while also maintaining updated security patches for all kernel components to prevent similar vulnerabilities from being exploited in the future.
The root cause of this vulnerability highlights the complexity of kernel-level memory management and the critical importance of proper state validation in network protocol implementations. The flaw demonstrates how seemingly minor configuration options like IPV6_RECVPKTINFO can create cascading effects when combined with improper error handling in kernel code paths. Organizations should implement robust patch management processes and regularly audit their kernel versions to ensure they are running supported and secure versions, particularly in mission-critical environments where availability is paramount. The vulnerability also underscores the need for comprehensive security testing of kernel components, especially those handling network packet processing and memory allocation in multi-threaded environments where race conditions and state management issues can lead to serious security implications.