CVE-2026-80986

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net/smc: bound the peer rkey counts in SMC-Rv2 LLC messages

On a link whose device has max_recv_sge == 1 there is no shared v2 receive

buffer, and smc_llc_save_add_link_rkeys() takes the v2 extension from 44

bytes past the start of the queue entry's inline message:

ext = (struct smc_llc_msg_add_link_v2_ext *)(llc_msg + SMC_WR_TX_SIZE);

The entry is a 72-byte allocation and the extension starts at offset 68, so

ext->num_rkeys at offset 94 is already past it. This happens on every

SMC-Rv2 link addition, whatever the peer sends:

[ 2.490065] BUG: KASAN: slab-out-of-bounds in smc_llc_save_add_link_rkeys+0x333/0x350

[ 2.490431] Read of size 2 at addr ffff8880056406de by task smctest/106

[ 2.490709]

[ 2.490792] CPU: 0 UID: 0 PID: 106 Comm: smctest Not tainted 7.2.0-rc5-p1-g77a5d9d9c99f #32 PREEMPT(lazy)

[ 2.490795] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIO

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References