# CVE-2026-18726: open-iscsi infinite loop in ICMPv6 Router Advertisement parsing

Source: https://junglewise.ai/threats/cve-2026-18726-open-iscsi-infinite-loop-in-icmpv6-router-advertisement-parsing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-12. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-18726 · Severity: medium · CVSS 6.5 · Published 2026-08-12

open-iscsi is a utility for managing iSCSI network storage connections on Linux systems. A flaw in the iscsiuio daemon allows an attacker on the same local network to send a crafted IPv6 Router Advertisement message that triggers an infinite loop, consuming CPU resources and making the daemon unresponsive. This impacts system availability for any infrastructure relying on iSCSI storage connectivity.

## Quick answers

**Is CVE-2026-18726 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18726 being exploited in the wild.

**How severe is CVE-2026-18726?** Medium severity, with a CVSS score of 6.5, published 12 August 2026.

**Which products and versions are affected?** open-iscsi open-iscsi.

**Is there a fix for CVE-2026-18726?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-18726 attacked?** It is attacked from the adjacent network, in a software library.

**Am I affected by CVE-2026-18726?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This vulnerability is an infinite loop (CWE-835) in open-iscsi's iscsiuio daemon when parsing specially crafted ICMPv6 Router Advertisement packets with zero-length options. The attack requires network adjacency (same Layer 2 segment) and an IPv6-enabled interface, but no authentication or user interaction. A successful exploit causes sustained CPU consumption, rendering the daemon unresponsive and degrading system availability. A secondary risk of out-of-bounds reads exists with short IPv6 payloads, though no confirmed memory corruption or data exposure has been observed. Mitigation involves filtering ICMPv6 type 134 messages or disabling IPv6 RA processing on affected interfaces.

## Affected products

- open-iscsi open-iscsi

## Timeline

- 2026-08-12: disclosed

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-18726](https://access.redhat.com/security/cve/CVE-2026-18726)