CVE-2014-2889 in Linux
Summary
by MITRE
Off-by-one error in the bpf_jit_compile function in arch/x86/net/bpf_jit_comp.c in the Linux kernel before 3.1.8, when BPF JIT is enabled, allows local users to cause a denial of service (system crash) or possibly gain privileges via a long jump after a conditional jump.
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Analysis
by VulDB Data Team • 05/12/2026
The vulnerability identified as CVE-2014-2889 represents a critical off-by-one error within the Linux kernel's BPF (Berkeley Packet Filter) Just-In-Time compilation subsystem. This flaw exists specifically in the bpf_jit_compile function located in arch/x86/net/bpf_jit_comp.c and affects Linux kernel versions prior to 3.1.8. The issue manifests when BPF JIT compilation is enabled, which is a performance optimization feature that translates BPF bytecode into native machine code for faster execution. The vulnerability stems from improper bounds checking during the compilation process, creating a scenario where memory access occurs beyond allocated boundaries.
The technical exploitation of this vulnerability involves manipulating BPF programs to trigger a conditional jump followed by a long jump that exceeds the allocated buffer space. This off-by-one error creates a situation where the JIT compiler generates machine code that accesses memory locations beyond the intended boundaries, potentially causing kernel memory corruption. The flaw can be leveraged by local users to either induce a system crash through kernel memory corruption or potentially escalate privileges by manipulating the execution flow of the JIT compiler. This represents a classic buffer overflow scenario where the bounds checking mechanism fails to properly validate jump destinations, leading to unauthorized memory access patterns.
The operational impact of CVE-2014-2889 extends beyond simple denial of service to potentially enable privilege escalation attacks. When exploited successfully, the vulnerability allows local attackers to execute arbitrary code with kernel privileges, compromising the entire system's security posture. Systems running affected kernel versions with BPF JIT enabled become vulnerable to exploitation, particularly in environments where users might have the ability to load BPF programs or where BPF is used for network packet filtering. The vulnerability is particularly concerning because it affects the kernel's core networking infrastructure and can be triggered through legitimate BPF program execution paths, making detection and prevention challenging.
This vulnerability maps directly to CWE-121, which describes "Stack-based Buffer Overflow" and CWE-125, which covers "Out-of-bounds Read" conditions. The ATT&CK framework categorizes this as a privilege escalation technique under T1068, which involves exploiting vulnerabilities to gain higher-level privileges. The attack surface is particularly wide given that BPF is extensively used in network monitoring, security tools, and system administration utilities. Organizations using Linux systems with BPF JIT enabled should prioritize patching to address this vulnerability, as the potential for system compromise makes this a critical security concern. The vulnerability also highlights the importance of proper bounds checking in kernel-level code and demonstrates how seemingly minor programming errors in low-level system components can have severe security implications.
Mitigation strategies for CVE-2014-2889 primarily involve upgrading to Linux kernel versions 3.1.8 or later where the vulnerability has been patched. System administrators should also consider disabling BPF JIT compilation through kernel parameters if the functionality is not required, as a temporary workaround. Additionally, monitoring for unusual BPF program loading activities and implementing proper access controls to limit who can load BPF programs can help reduce the attack surface. Security teams should also conduct vulnerability assessments to identify systems running affected kernel versions and prioritize remediation efforts based on the criticality of the affected systems within their infrastructure.