Open-iscsi: open-iscsi: integer underflow in iscsiuio ipv4 dhcp parsing
Published Aug 13, 2026
6.5
MEDIUMCVSS 3.1
EPSS 0.19%
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.
Affected products
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||
|---|---|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | affected |
| |||
| Red Hat | Red Hat Enterprise Linux 9 | affected |
|
- 9.0
- 10.0
No data.
Red Hat Enterprise Linux 10
iscsi-initiator-utils
Fix deferred
Red Hat Enterprise Linux 9
iscsi-initiator-utils
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | iscsi-initiator-utils | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | iscsi-initiator-utils | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
Vendor solution
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.
Red Hat statement
This flaw in `iscsi-initiator-utils` is rated Moderate. It allows an adjacent-network attacker to trigger a denial of service by sending a crafted IPv4/UDP DHCP reply to systems where `iscsiuio` is configured to use IPv4 DHCP. Exploitation requires specific network conditions and a vulnerable configuration, limiting its broader impact.
Red Hat mitigation
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.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
PartialDecision
n/aAssessed Aug 14, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
Aug–Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.19% (0.00190) | 7.79th | v5 (v2026.06.15) |
| Aug 13, 2026 | 0.20% (0.00198) | 9.88th | v5 (v2026.06.15) |
References (4)
- https://access.redhat.com/security/cve/CVE-2026-18728 vdb-entryx_refsource_REDHATVendor AdvisoryMitigation
- https://bugzilla.redhat.com/show_bug.cgi?id=2463029 issue-trackingx_refsource_REDHATIssue TrackingVendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-18728
- https://www.cve.org/CVERecord?id=CVE-2026-18728
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2026-18728 | vdb-entryx_refsource_REDHATVendor AdvisoryMitigation | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2463029 | issue-trackingx_refsource_REDHATIssue TrackingVendor Advisory | |
| https://nvd.nist.gov/vuln/detail/CVE-2026-18728 | ||
| https://www.cve.org/CVERecord?id=CVE-2026-18728 |
Change history (0)
No recorded changes yet.