CVE-2024-46764 in Linux
Summary
by MITRE • 09/18/2024
In the Linux kernel, the following vulnerability has been resolved:
bpf: add check for invalid name in btf_name_valid_section()
If the length of the name string is 1 and the value of name[0] is NULL
byte, an OOB vulnerability occurs in btf_name_valid_section() and the return value is true, so the invalid name passes the check.
To solve this, you need to check if the first position is NULL byte and if the first character is printable.
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Analysis
by VulDB Data Team • 04/06/2026
The vulnerability identified as CVE-2024-46764 resides within the Linux kernel's BPF (Berkeley Packet Filter) subsystem, specifically in the BTF (BPF Type Format) name validation mechanism. This issue manifests in the btf_name_valid_section() function which is responsible for validating name strings within BTF data structures. The flaw represents a critical oversight in input validation that could potentially allow malicious actors to bypass security checks through carefully crafted invalid name strings. The vulnerability is particularly concerning because it affects the foundational type validation mechanisms that underpin BPF program execution and security boundaries within the kernel.
The technical implementation flaw occurs when processing name strings where the first character is a null byte with a length of one character. Under normal circumstances, such a string should be rejected as invalid due to its non-printable nature and lack of meaningful content. However, the current implementation fails to properly validate this edge case, leading to an out-of-bounds memory access condition. When the function encounters a name string with a single null byte, it incorrectly returns a true value indicating the name is valid, thereby allowing invalid data to pass through the validation layer. This improper validation stems from the absence of a comprehensive check that verifies both the null byte condition and the printable character requirement for the first position in the name string.
The operational impact of this vulnerability extends beyond simple validation failures and could potentially enable privilege escalation or arbitrary code execution within the kernel context. Attackers could exploit this weakness by crafting BPF programs with maliciously formatted name strings that bypass the validation checks, subsequently leading to memory corruption or information disclosure. The vulnerability affects systems running Linux kernels that implement BPF and BTF functionality, particularly those utilizing eBPF programs for network filtering, system monitoring, or security policy enforcement. Given that BPF is widely used across modern Linux distributions for various security and performance monitoring tasks, the potential attack surface is substantial.
Mitigation strategies for CVE-2024-46764 should focus on implementing proper input validation that explicitly checks for null bytes in the first position of name strings while also verifying that the first character meets printable character requirements. The fix requires modifying the btf_name_valid_section() function to incorporate additional validation logic that prevents null byte strings from passing validation. Organizations should prioritize applying kernel updates that contain the patched implementation, as this vulnerability could be exploited to gain elevated privileges or compromise system integrity. Security teams should also monitor for any potential exploitation attempts targeting BPF subsystems and consider implementing additional runtime protections for BPF program loading and execution. The fix aligns with established security practices for preventing buffer overflows and input validation attacks, addressing the underlying CWE-121 buffer overflow vulnerability pattern and potentially mapping to ATT&CK techniques related to privilege escalation through kernel vulnerabilities.