CVE-2026-53076— bpf: Fix OOB in pcpu_init_value

bpf: Fix OOB in pcpu_init_value

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix OOB in pcpu_init_value An out-of-bounds read occurs when copying element from a BPF_MAP_TYPE_CGROUP_STORAGE map to another pcpu map with the same value_size that is not rounded up to 8 bytes. The issue happens when: 1. A CGROUP_STORAGE map is created with value_size not aligned to 8 bytes (e.g., 4 bytes) 2. A pcpu map is created with the same value_size (e.g., 4 bytes) 3. Update element in 2 with data in 1 pcpu_init_value assumes that all sources are rounded up to 8 bytes, and invokes copy_map_value_long to make a data copy, However, the assumption doesn't stand since there are some cases where the source may not be rounded up to 8 bytes, e.g., CGROUP_STORAGE, skb->data. the verifier verifies exactly the size that the source claims, not the size rounded up to 8 bytes by kernel, an OOB happens when the source has only 4 bytes while the copy size(4) is rounded up to 8.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

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Linux kernel 安全漏洞

Linux kernel是美国Linux基金会开源的操作系统Linux所使用的内核。 Linux kernel存在越界读漏洞，该漏洞源于pcpu_init_value中出现越界读取，当从一个BPF_MAP_TYPE_CGROUP_STORAGE映射复制元素到另一个具有相同value_size且未向上取整到8字节的pcpu映射时，可能导致越界读取。

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