CVE-2026-80584
Description
A flaw was found in the Linux kernel's s390/qeth component. This vulnerability allows a local attacker to trigger an integer underflow when handling user-supplied buffer lengths in the qeth_snmp_command() and qeth_l3_arp_query() functions. This can lead to an out-of-bounds write, potentially causing memory corruption and system instability or a denial of service.
Statement
A kernel heap out of bounds write is possible in the s390 qeth SNMP and ARP query ioctl paths because qeth_snmp_command() and qeth_l3_arp_query() accept a user supplied udata_len that can be smaller than the fixed reply offset. The later bounds check subtracts udata_offset from udata_len using u32 arithmetic, so a too small length can underflow and make the check pass before memcpy writes past the allocated buffer. For the CVSS the PR:L is used because a local user or process can reach the ioctl interface in plausible deployments, while full administrator privileges are not clearly required by the bug class. The issue is not directly network reachable because the trigger is a local ioctl rather than packet traffic. Impact is at least a local denial of service via kernel crash and in the paranoid case may allow confidentiality and integrity impact due to kernel heap memory corruption.
Mitigation
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 | 7.8 | N/A | 8.4 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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