Description

Heap-based buffer overflow in Windows iSCSI Target Service allows an unauthorized attacker to execute code over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-11T17:18:59.053Z",
  "pubdate": "2026-08-11T17:18:59.053Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability exists within the Windows iSCSI Target Service, representing a critical security flaw in network-accessible storage management infrastructure. The vulnerability allows an unauthorized, remote threat actor to achieve arbitrary code execution over the network without requiring prior authentication or user interaction.\nThe affected product is the Windows iSCSI Target Service, which handles storage networking requests. The presence of a heap-based buffer overflow indicates that improper memory management during the processing of incoming data packets leads to memory corruption. This structural defect allows malicious input to overwrite adjacent heap memory structures, potentially hijacking control flow.\nThe risk implications are severe, as successful exploitation grants the attacker full system-level execution capabilities within the context of the service. This compromises the confidentiality, integrity, and availability of the affected host and any dependent storage resources. Given the network exposure of the iSCSI service, systems directly accessible via TCP/IP are at immediate risk of automated or targeted exploitation.\nAttackers do not require valid credentials or local access, lowering the barrier to entry for potential campaigns. Remediation requires applying vendor-supplied security updates or restricting network access to trusted management interfaces.",
  "technicalDetails": "The vulnerability resides in the Windows iSCSI Target Service, specifically within the routine responsible for parsing and processing incoming network protocol data structures on the listening port. The root cause is a classic heap-based buffer overflow stemming from insufficient bounds checking and input validation prior to copying data into dynamically allocated heap memory buffers.\nWhen a client establishes a connection and transmits maliciously crafted iSCSI protocol messages, the vulnerable component calculates destination buffer sizes incorrectly or fails to enforce strict limits on incoming payload lengths. Consequently, a larger sequence of bytes than anticipated is written into the heap chunk, resulting in memory corruption of adjacent heap metadata or adjacent object payloads.\nThe exploitation method leverages this heap corruption to manipulate internal application state, function pointers, or object virtual method tables (vptrs). By carefully engineering the size and content of the malicious payload, an attacker can coerce the service into executing arbitrary shellcode or leveraging Return-Oriented Programming (ROP) chains. Because the Windows iSCSI Target Service typically operates with elevated privileges, successful control flow hijacking yields immediate code execution at a high privilege level.\nThe attack flow proceeds as follows: First, the unauthorized attacker establishes a TCP connection to the Windows iSCSI Target Service over the network. Second, the attacker transmits a specially formatted iSCSI request containing an oversized data payload designed to exceed the allocated heap buffer boundaries. Third, the parsing engine processes the payload, triggering the heap overflow and corrupting adjacent heap structures. Finally, the corrupted memory state is leveraged to redirect execution flow to attacker-supplied instructions, resulting in full system compromise.\nThe vulnerability requires network exposure, typically over standard iSCSI TCP ports. No authentication or privileges are required to initiate the attack sequence, making it exploitable by any network-adjacent entity capable of reaching the target service."
}