CVE-2026-53076

About vulnerability

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.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , TuxCare 9.6 ESU

Affected packages:

kernel @ 5.10.0 (+5 more)

Live-patch status from KernelCare for each operating system.