CVE-2025-22087 is a vulnerability identified in the Linux kernel's Berkeley Packet Filter (BPF) subsystem. The issue stems from an array bounds error related to the function may_goto, which uses an additional 8 bytes on the stack. This extra stack usage causes the interpreters[] array to be accessed out of bounds when the index is calculated based on the stack size. Specifically, when a BPF program is rewritten, the stack size must be re-evaluated to prevent this out-of-bounds access. For non-JIT (Just-In-Time compilation) cases, the kernel rejects loading the program directly if the stack size is miscalculated. However, in some non-JIT scenarios, the calculation of interpreters[idx] may still cause out-of-bounds access, which the kernel currently only warns about rather than blocking. For JIT-compiled BPF programs, additional warnings are implemented regarding the execution of bpf_func, and the function __bpf_prog_ret0_warn has been moved out of the macro definition CONFIG_BPF_JIT_ALWAYS_ON to better handle these cases. The vulnerability arises from improper bounds checking in the BPF interpreter's handling of stack size and indexing, which could potentially lead to memory corruption or unexpected behavior within the kernel's BPF execution environment. Although no known exploits are currently reported in the wild, the nature of the vulnerability suggests that a crafted BPF program could trigger out-of-bounds memory access, potentially leading to kernel crashes or privilege escalation if exploited. The vulnerability affects Linux kernel versions identified by the commit hash 011832b97b311bb9e3c27945bc0d1089a14209c9 and likely other versions sharing the same code base. The fix involves re-evaluating stack size when rewriting BPF programs, rejecting unsafe programs in non-JIT cases, and adding warnings for potentially unsafe operations in both JIT and non-JIT contexts.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Linux in servers, cloud infrastructure, and embedded systems. Exploitation could lead to kernel crashes, resulting in denial of service, or potentially privilege escalation, allowing attackers to gain unauthorized access to sensitive systems. This is particularly critical for sectors relying heavily on Linux-based infrastructure such as finance, telecommunications, government, and critical infrastructure. The BPF subsystem is commonly used for network packet filtering, monitoring, and security enforcement, so a vulnerability here could undermine network security controls or monitoring tools. Additionally, cloud service providers and data centers operating in Europe that use Linux extensively could face service disruptions or compromise of tenant isolation. Although no active exploits are known, the complexity and low-level nature of the vulnerability mean that sophisticated attackers could develop exploits, especially targeting high-value infrastructure. The impact on confidentiality, integrity, and availability could be severe if exploited, affecting business continuity and regulatory compliance under frameworks such as GDPR and NIS Directive.

European organizations should prioritize updating their Linux kernel to the latest patched versions that address CVE-2025-22087. Since the vulnerability involves BPF program loading and execution, administrators should audit and restrict the ability to load or run untrusted BPF programs, especially on multi-tenant or shared systems. Employing kernel lockdown features and mandatory access controls (e.g., SELinux, AppArmor) can limit the impact of potential exploitation. Monitoring kernel logs for warnings related to BPF program loading and execution may help detect attempts to exploit this vulnerability. For environments using Just-In-Time compilation of BPF programs, ensure that kernel configurations are updated to include the latest fixes, including the changes to __bpf_prog_ret0_warn handling. Network security teams should also review the use of BPF-based tools and consider temporary disabling or restricting their use until patches are applied. Finally, organizations should engage in vulnerability management processes that include testing patches in staging environments before deployment to production to avoid service disruptions.