# CVE-2026-18728: Open-iscsi: open-iscsi: integer underflow in iscsiuio ipv4 dhcp parsing

> A remote attacker on the local network can crash the iscsiuio process via a crafted DHCP reply, causing denial of service in open-iscsi.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** AZL-95919, DEBIAN-CVE-2026-18728, GHSA-v5q9-q65g-v5rv, UBUNTU-CVE-2026-18728

## What is CVE-2026-18728?

CVE-2026-18728 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 13 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-18728?

It affects 1 product.


Products: Redhat Enterprise Linux.

## How do I fix CVE-2026-18728?

Apply the vendor's patch.

## Is CVE-2026-18728 being exploited?

There is no known exploitation of CVE-2026-18728 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2018-14667](https://insights.sbomify.com/CVE-2018-14667/): Red Hat JBoss RichFaces Framework Expression Language Injection (critical 9.8, exploited in the wild)
- [CVE-2021-20325](https://insights.sbomify.com/CVE-2021-20325/): Missing fixes for CVE-2021-40438 and CVE-2021-26691 in the versions of httpd, as shipped in Red Hat Enterprise Linux 8.5.0, causes a securit (critical 9.8)
- [CVE-2018-25011](https://insights.sbomify.com/CVE-2018-25011/): Memory corruption in libwebp (critical 9.8)
- [CVE-2018-25014](https://insights.sbomify.com/CVE-2018-25014/): Other in libwebp (critical 9.8)
- [CVE-2014-3585](https://insights.sbomify.com/CVE-2014-3585/): Supply chain in redhat-upgrade-tool (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18728 and fix it if it is affected.

What it is: CVE-2026-18728 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 13 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-18728 in the wild and no public exploit code.

Affected product: Redhat Enterprise Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-18728/ (Markdown: https://insights.sbomify.com/CVE-2026-18728/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18728
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18728
- OSV: https://osv.dev/vulnerability/CVE-2026-18728

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18728/
Summaries are generated and may contain mistakes; the official description above is the record.