Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to bypass security restrictions due to an interpretation conflict in the multipart parser.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "3.0",
  "pubDate": "2026-08-12T17:17:25.527Z",
  "pubdate": "2026-08-12T17:17:25.527Z",
  "executiveSummary": "A security restriction bypass vulnerability has been identified in IBM i versions 7.3, 7.4, 7.5, and 7.6.\nThe vulnerability arises due to an interpretation conflict within the multipart parser, potentially allowing a remote authenticated attacker to bypass established security controls and restrictions.\nThe primary impact of this flaw involves unauthorized circumvention of security enforcement mechanisms, which could subvert access controls or data validation boundaries.\nExploitation of this vulnerability requires the attacker to be authenticated remotely, granting them the capability to leverage parser discrepancies for unauthorized operations.\nOrganizations utilizing the affected IBM i operating system versions face potential risk to data integrity and boundary enforcement if attackers successfully exploit the interpretation conflict.\nRemediation requires applying official vendor patches or updates as provided by IBM to resolve the underlying multipart parsing logic discrepancy.",
  "technicalDetails": "The vulnerability is rooted in an interpretation conflict occurring within the multipart parser component of IBM i versions 7.3, 7.4, 7.5, and 7.6.\nMultipart parsers are responsible for dissecting complex HTTP or MIME-encoded requests containing multiple data sections, typically separated by defined boundaries.\nAn interpretation conflict occurs when the parser evaluates input data differently than downstream security filters or authorization engines, creating a parsing discrepancy.\nAttackers can exploit this behavior by crafting specially formatted multipart payloads designed to exploit differences in how boundaries, headers, or body segments are interpreted.\nThe attack flow begins with a remote authenticated attacker submitting a malformed or ambiguously constructed multipart request to the target IBM i system.\nUpon receipt, the vulnerable multipart parser processes the request inconsistently, failing to correctly identify or enforce security policies against specific payload segments.\nThis mismatch allows restricted content, commands, or data structures to bypass validation routines and reach protected internal application logic.\nAuthentication is a prerequisite for exploitation, meaning the attacker must possess valid credentials and network access to interact with the vulnerable service.\nThe technical impact centers around security restriction bypass, enabling unauthorized interactions or access that should normally be blocked by the parsing and filtering subsystems.\nNo specific privileges beyond standard remote authentication are explicitly mandated to attempt the vector, provided the attacker can invoke the parsing mechanism."
}