---
id: "CVE-2026-115486"
kind: "vulnerability"
aliases: ["CVE-2026-115486"]
title: "open-iscsi iscsiuio: IPv6 neighbor packets let attackers poison ARP tables"
severity: "high"
cvss: 7.1
epss: 0.00206
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "open-iscsi", "fixed": [], "affected": "all versions (no fixed version published; Debian 2.1.8-2.1.13 listed vulnerable)", "ecosystem": "linux"}]
ecosystems: []
tags: ["infrastructure", "ipv6", "iscsi", "iscsiuio", "layer2", "linux", "open-iscsi", "self-hosted"]
not_affected_if: ["no-iscsi", "no-iscsi-offload-hardware", "software-iscsi", "trusted-l2-segment"]
published_at: "2026-10-23T01:16:53+00:00"
first_seen_at: "2026-10-23T21:57:32+00:00"
updated_at: "2026-10-25T04:02:54+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-115486", "first_seen_at": "2026-10-23T21:57:32+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-115486", "first_seen_at": "2026-10-24T07:15:51+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-25T04:02:54+00:00"}]
---

# open-iscsi iscsiuio: IPv6 neighbor packets let attackers poison ARP tables

iscsiuio (open-iscsi) reads IPv6 Neighbor Discovery link-layer options without a length check and updates the ARP table from packet headers, so a host on the same L2 segment can poison ARP and redirect iSCSI traffic. Only hosts using iSCSI offload NICs (QLogic/Broadcom bnx2, bnx2x, qedi) with the iscsiuio daemon running are exposed. Software iSCSI (plain iscsid on ordinary NICs) and systems without offload hardware can skip it. Red Hat mitigation: keep iscsiuio interfaces on trusted L2 segments and filter ICMPv6 type 135/136 from untrusted sources.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- linux:open-iscsi affected all versions (no fixed version published; Debian 2.1.8-2.1.13 listed vulnerable) fixed ?

## How to check

Run 'systemctl status iscsiuio' or 'pgrep iscsiuio' to see whether the daemon runs, and 'iscsiadm -m iface' to look for bnx2i/qedi offload transports. If neither shows, you are not exposed. Check the package with 'dpkg -l open-iscsi' or 'rpm -q iscsi-initiator-utils'.

## Fix

unknown: no fixed open-iscsi version published as of 2026-10-25; Debian and Red Hat list it unfixed. Watch Red Hat Bugzilla 2556267 and the open-iscsi GitHub repo.

## Timeline

- 2026-10-23T21:57:32+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-115486
- 2026-10-24T07:15:51+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-115486
- 2026-10-25T04:02:54+00:00 analyst — Red Hat advisory read: affects only hosts with hardware iSCSI offload NICs (bnx2/bnx2x/qedi) where iscsiuio runs; no upstream fixed version published yet (Debian tracker: bookworm/trixie/forky/sid all vulnerable; CVE record has no affected range). Not exploited, no PoC found; EPSS ~0.002. Red Hat rates Moderate; severity kept. No dedicated who_is_affected flag in write, so it is in summary.

## Documents

- [advisory] Red Hat CVE-2026-115486 https://access.redhat.com/security/cve/CVE-2026-115486
- [advisory] CVE Record CVE-2026-115486 https://www.cve.org/CVERecord?id=CVE-2026-115486
- [mentions] Debian tracker: open-iscsi https://security-tracker.debian.org/tracker/source-package/open-iscsi

## From the sources

A flaw was found in the iscsiuio component of open-iscsi. The IPv6 Neighbor Discovery handler accesses link-layer address options at a fixed offset without verifying the packet contains them. Additionally, the ARP table is updated unconditionally with attacker-controlled addresses from the packet headers. An attacker on the same network segment can send a minimal Neighbor Advertisement to poison the ARP table and redirect network traffic.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_