CVE-2026-80584: Linux

High severity, CVSS 8.4. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux: from 2.6.26, before 5.10.266 (fixed in 5.10.266); from 5.11, before 5.15.217 (fixed in 5.15.217); from 5.16, before 6.1.184 (fixed in 6.1.184); from 6.2, before 6.6.153 (fixed in 6.6.153); from 6.7, before 6.12.105 (fixed in 6.12.105); from 6.13, before 6.18.46 (fixed in 6.18.46); …

Published 2026-08-26. Last modified 2026-08-27.