Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-08-26T00:00:00 kernel: s390/qeth: validate user buffer length in SNMP and ARP query ioctls 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-787

In the Linux kernel, the following vulnerability has been resolved: s390/qeth: validate user buffer length in SNMP and ARP query ioctls qeth_snmp_command() and qeth_l3_arp_query() allocate a buffer sized by a user-supplied length (udata_len) without checking a lower bound, then set udata_offset to a fixed non-zero value and pass both to a reply callback. The callback bounds-checks the copy with if ((udata_len - udata_offset) < len) Both fields are u32, so a udata_len smaller than udata_offset makes the subtraction wrap and the check pass, and the following memcpy() writes past the allocation. A udata_len of 0 also yields ZERO_SIZE_PTR from kzalloc(), which the existing NULL check does not catch. Reject buffers smaller than udata_offset before allocating, so the callback subtraction can no longer underflow.

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.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-80584 https://nvd.nist.gov/vuln/detail/CVE-2026-80584 https://lore.kernel.org/linux-cve-announce/2026082616-CVE-2026-80584-5dae@gregkh/T