CVE-2026-18728: Open-iscsi: open-iscsi: integer underflow in iscsiuio ipv4 dhcp parsing
Noroxi assessment
Priority: Monitor (action score 26/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.31% (FIRST EPSS).
- Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: azl3 iscsi-initiator-utils 2.1.12-1 on Azure Linux 3.0 Release Notes.
Low priority for now. Upgrade to azl3 iscsi-initiator-utils 2.1.12-1 on Azure Linux 3.0 Release Notes or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Aug 13, 2026
- Updated
- Nov 5, 2026
- EPSS
- 0.3% · 24th percentile
- CWE
- CWE-191
Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · redhat
- 6.5
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- redhat enterprise linux10.0
- redhat enterprise linux9.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
Red Hat Red Hat Enterprise Linux 10
- all versionsaffected
Red Hat Red Hat Enterprise Linux 9
- all versionsaffected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | open-iscsi | before 2.1.8-1+deb12u1 | 2.1.8-1+deb12u1 |
| Debian:13 | open-iscsi | from 0 | — |
| Debian:14 | open-iscsi | before 2.1.13-1 | 2.1.13-1 |
| openSUSE:Tumbleweed | open-iscsi | before 2.1.13-114.1 | 2.1.13-114.1 |
Same product
redhat: all recordsOther highest-scoring records for the same primary product.
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- CVE-2023-50387Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of ser60This week
- CVE-2017-5456A mechanism to bypass file system access protections in the sandbox using the file system request constructor through an IPC message.40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-18726Aug 12, 2026 · Open-iscsi: open-iscsi: denial of service in iscsiuio router advertisement parsing26Monitor
- ← EarlierCVE-2026-18727Aug 12, 2026 · Open-iscsi: open-iscsi: integer underflow in iscsiuio dhcpv6 parsing26Monitor
- Later →CVE-2026-73583Aug 13, 2026 · Sblim-sfcb: unsafe deserialization in sblim-sfcb provider-manager ipc allows out-of-bounds memory access via malformed operationhdr26Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| azl3 iscsi-initiator-utils 2.1.12-1 on Azure Linux 3.0 | Release Notes | Microsoft (MSRC) |
| debian:open-iscsi | 2.1.13-1 · Debian:14 | Package registry (OSV) |
| debian:open-iscsi | 2.1.8-1+deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:open-iscsi | 2.1.13-114.1 · openSUSE:Tumbleweed | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- In partnershipRed Hat (Aisle.com) and Keith Linneman (Linneman Labs)
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-187271 days apartOpen-iscsi: open-iscsi: integer underflow in iscsiuio dhcpv6 parsing26Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone on the same network segment can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Adjacent
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-191 · Integer Underflow (Wrap or Wraparound)CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.