CVE-2026-100074
Description
A flaw was found in the Linux kernel's extended Berkeley Packet Filter (eBPF) subsystem. The BPF Type Format (BTF) validator failed to enforce that reference count (bpf_refcount) fields are unique within data structures. A local user with permissions to load eBPF programs could exploit this flaw by providing a malformed BTF structure containing multiple reference count fields, leading to a kernel crash and resulting in a Denial of Service (DoS).
Statement
This vulnerability is rated as Low severity because successful exploitation requires elevated privileges to load custom eBPF programs, limiting the blast radius on Red Hat Enterprise Linux. By default, unprivileged eBPF execution is disabled across supported Red Hat Enterprise Linux releases, preventing unprivileged local users from injecting malformed BTF data structures. As a result, only authorized users or processes with administrative capabilities such as CAP_BPF or CAP_SYS_ADMIN can interact with the affected subsystem.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
If an adversary can prevent a reference count from reaching zero, then resources might not be released when they are supposed to, thus causing resources to become scarce for future needs.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If an adversary can cause a reference count to reach zero when the resource is still in use, then a resource might be released before it is supposed to be, possibly forcing an error that causes the product to crash or exit out of its current operation.
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