CVE-2026-74514
Description
A flaw was found in the KVM (Kernel-based Virtual Machine) s390 PCI component. Incorrect memory accounting in the account_mem() and unaccount_mem() functions, specifically related to the handling of pinned and unpinned pages, can lead to a resource leak. This occurs because the reference count for user structures is not properly decremented, and memory accounting might be performed in a different process context than the one that originally pinned the pages. This issue could potentially lead to resource exhaustion, resulting in a Denial of Service (DoS) for the system.
Statement
This vulnerability is rated as having a Low impact because exploitation is constrained to IBM Z (s390x) environments utilizing KVM with PCI device pass-through and requires local execution privileges. Systems running on other architectures or installations without KVM PCI assignments are unaffected by this defect. In affected configurations, an unprivileged local user could trigger memory accounting leaks that gradually deplete system resources, resulting in a denial-of-service condition without compromising data confidentiality or integrity.
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 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: 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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