Linux Kernel bpf out-of-bounds

Summaryinfo

A vulnerability identified as very critical has been detected in Linux Kernel. This issue affects some unknown processing of the component bpf. The manipulation leads to out-of-bounds. This vulnerability is referenced as CVE-2026-98149. Remote exploitation of the attack is possible. No exploit is available. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability was found in Linux Kernel (affected version not known). It has been rated as very critical. This issue affects some unknown functionality of the component bpf. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix percpu map update indexing with sparse CPU IDs Per-CPU array, hash, and cgroup storage map updates without BPF_F_CPU or BPF_F_ALL_CPUS use a value buffer whose per-CPU slots are packed in possible-CPU order. The buffer is sized as: round_up(value_size, 8) * num_possible_cpus() The update paths iterate over possible CPUs, but use the logical CPU ID to calculate the source offset: value + size * cpu This only works when possible CPU IDs are contiguous starting at zero. For example, with a possible CPU mask of 0,2-3, the buffer contains three slots corresponding to CPUs 0, 2, and 3. CPU2 is therefore expected to use slot 1 and CPU3 slot 2. Instead, the current code uses slots 2 and 3 respectively, causing incorrect per-CPU values and an out-of-bounds read from the update buffer for CPU3. The corresponding lookup paths already use a dense offset while iterating over possible CPUs. Do the same for the array, hash, and cgroup storage update paths, advancing the source offset once for each possible CPU. BPF_F_ALL_CPUS continues to use the same value for every CPU.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-98149 since 09/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/25/2026).

Applying the patch c16c62c91e5d6737a9fbb0a541b8b34610470a2b/75b0a6db4300e4c2c9e97a0848deaa7acfb42fb7 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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