CVE-2026-53076
Received Received - Intake
Out-of-Bounds Read in Linux Kernel BPF

Publication date: 2026-06-24

Last updated on: 2026-06-24

Assigner: kernel.org

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.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2026-06-24
Last Modified
2026-06-24
Generated
2026-06-25
AI Q&A
2026-06-24
EPSS Evaluated
N/A
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Quick Actions
Instant insights powered by AI
Executive Summary

This vulnerability is an out-of-bounds (OOB) read in the Linux kernel related to BPF (Berkeley Packet Filter) maps. Specifically, it occurs when copying an element from a BPF_MAP_TYPE_CGROUP_STORAGE map to another per-CPU (pcpu) map that has the same value_size but is not rounded up to 8 bytes.

The problem arises because the pcpu_init_value function assumes all source values are rounded up to 8 bytes. However, some sources like CGROUP_STORAGE maps may have value sizes not aligned to 8 bytes (for example, 4 bytes). When copying data, the kernel rounds the copy size up to 8 bytes, but the verifier only checks the actual source size (e.g., 4 bytes). This mismatch causes an out-of-bounds read when the copy tries to access beyond the actual source data.

Impact Analysis

This out-of-bounds read vulnerability can lead to the kernel reading memory beyond the intended buffer. Such memory access errors can cause system instability, crashes, or potentially expose sensitive kernel memory contents to an attacker.

Because this issue occurs in the kernel's BPF subsystem, which is often used for networking and security monitoring, exploitation could allow attackers to gain unintended access to kernel memory, potentially leading to privilege escalation or information disclosure.

Chat Assistant
Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-53076. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70
EPSS Chart