Description

Heap-based buffer overflow in Windows Kerberos allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:27.713Z",
  "pubdate": "2026-08-11T17:18:27.713Z",
  "executiveSummary": "This vulnerability is classified as a heap-based buffer overflow affecting the Windows Kerberos protocol implementation. The flaw allows an authenticated local attacker to achieve elevation of privileges on targeted systems. The primary impact of successful exploitation includes the compromise of host integrity and the potential acquisition of system-level privileges.\nThe affected product is the Windows Kerberos authentication component. The risk implications are severe, as an attacker with standard user privileges can leverage this vulnerability to execute arbitrary code within the context of a privileged system service.\nExploitation requirements dictate that the attacker must possess local access to the vulnerable system and valid authentication credentials. Attack capability is constrained to local execution, meaning remote exploitation is not facilitated by this specific flaw. The vulnerability exposes weaknesses in memory management operations during ticket processing and validation routines.",
  "technicalDetails": "The vulnerability resides in the heap management routines of the Windows Kerberos component responsible for parsing and processing authentication messages. The root cause stems from improper boundary checking and insufficient validation of input lengths when allocating and writing data to heap-allocated buffers during specific protocol operations.\nWhen an authorized attacker submits a specially crafted sequence of Kerberos requests or ticket structures, the vulnerable component miscalculates the required buffer size for heap allocation. This leads to a heap-based buffer overflow condition where input data exceeds the boundaries of the allocated heap chunk, resulting in the corruption of adjacent heap metadata and adjacent object structures.\nThe attack flow begins with the local attacker establishing a session or leveraging existing local execution capabilities to interact with the vulnerable Kerberos service or local security authority subsystems. The attacker crafts a malicious payload encapsulated within valid authentication parameters or protocol messages. Upon submission, the vulnerable function processes the input, triggers the heap overflow, and overwrites critical function pointers or sensitive data structures residing on the heap.\nThe vulnerable component involves the internal parsing logic of the Kerberos protocol handler within the Windows operating system. Authentication requirements mandate that the attacker is authenticated to the local machine, while privilege requirements necessitate low-level standard user access. Network exposure is localized, as the attack vector requires local interaction rather than direct remote network accessibility.\nPost-exploitation impact includes arbitrary code execution with elevated privileges. By successfully manipulating heap layouts and hijacking control flow, the attacker can execute payloads as a privileged user or system account, leading to complete compromise of the local host security boundary and enabling further credential harvesting or lateral movement within the enterprise environment."
}