Open-iscsi: open-iscsi: integer underflow in iscsiuio ipv4 dhcp parsing
Summary
| CVE | CVE-2026-18728 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-13 04:17:19 UTC |
| Updated | 2026-08-14 23:16:31 UTC |
| Description | A flaw was found in open-iscsi. An integer underflow vulnerability in the `iscsiuio` component, specifically during IPv4 Dynamic Host Configuration Protocol (DHCP) parsing, allows a remote attacker on the same local network segment to cause a denial of service. By sending a specially crafted IPv4/UDP DHCP reply, the attacker can trigger an out-of-bounds read, leading to the `iscsiuio` process crashing. This issue affects systems where `iscsiuio` is actively handling IPv4 DHCP traffic. |
Risk And Classification
Primary CVSS: v3.1 6.5 MEDIUM from [email protected]
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.001980000 probability, percentile 0.099760000 (date 2026-08-16)
Problem Types: CWE-191 | CWE-191 Integer Underflow (Wrap or Wraparound)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 6.5 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 6.5 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-18728 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Keith Linneman (Linneman Labs) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-04-26T20:41:55.000Z | Reported to Red Hat. |
| CNA | 2026-08-12T18:05:24.879Z | Made public. |
Workarounds
CNA: To mitigate this issue, restrict network access to `iscsiuio`-managed interfaces. Configure firewall rules to limit DHCP/BOOTP traffic to only trusted infrastructure within the local broadcast domain. This reduces the exposure to untrusted systems that could send crafted IPv4 DHCP packets. If `iscsiuio` is actively using IPv4 DHCP, consider reconfiguring it to use static IP addresses or a different network configuration if feasible. Changes to network configuration may require a service restart.