CVE-2026-53076

/// Technical description

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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References