CVE-2026-115484
Description
A flaw was found in the iscsiuio component of open-iscsi. The DHCPv4 option parser incorrectly calculates the length of the options data, causing it to read beyond the allocated buffer into adjacent heap memory. An attacker on the same network segment can send a crafted DHCP response to crash the daemon or corrupt its network configuration.
Statement
This flaw is rated Moderate because exploitation requires adjacent-network access to a Layer 2 segment where iscsiuio is processing IPv4 DHCP traffic on a hardware iSCSI offload NIC (Broadcom bnx2/bnx2x or QLogic qedi). Systems without iSCSI offload hardware are not affected. The iscsiuio daemon is socket-activated and only runs when the hardware is present and configured. iSCSI storage networks are typically isolated from general-purpose networks, further limiting attacker access.
Mitigation
Restrict untrusted systems from the L2 broadcast domain where iscsiuio-managed interfaces operate. If IPv4 DHCP is not required for iSCSI boot, configure static IP addressing. Where DHCP must remain enabled, limit DHCP/BOOTP traffic so only trusted infrastructure can reach the affected host.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.6 | N/A | 7.6 |
| Attack Vector | Adjacent Network | N/A | Adjacent Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
cve.org: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Red Hat CVSS v3 Score Explanation
DHCPv4 parse_msg 240-byte heap OOB read. C:L — heap data leaks into network config but attacker cannot observe it directly. I:L — attacker-influenced config via heap data. A:H — 240 bytes can cross page boundary, SEGV confirmed. Kept at 7.1 per AV:A OOB precedent review.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
Acknowledgements
Red Hat would like to thank Tristan Madani (Talence Security) for reporting this issue.
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