Description

IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to cause a denial of service due to a buffer overflow.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.2",
  "pubDate": "2026-08-13T21:17:42.687Z",
  "pubdate": "2026-08-13T21:17:42.687Z",
  "executiveSummary": "A buffer overflow vulnerability exists in IBM i versions 7.6, 7.5, 7.4, and 7.3 that can be exploited by a remote attacker to induce a denial of service condition. The vulnerability arises from improper memory handling when processing untrusted inputs, allowing remote threat actors to corrupt memory structures within vulnerable components of the operating system.\nThe primary impact of successful exploitation is service disruption, potentially causing critical system functions or network-facing services to crash, thereby denying legitimate access to system resources. The risk implication is high for operational availability, as an attacker with network connectivity can trigger the fault without necessarily requiring complex authentication or prior privileges, depending on the specific vulnerable vector exposed.\nExploitation requirements are dictated by the network accessibility of the vulnerable service on the target IBM i system. The attack capabilities are strictly limited to causing a denial of service based on the provided description, as the buffer overflow manifests in a manner that disrupts execution flow or triggers memory access violations rather than achieving arbitrary code execution.",
  "technicalDetails": "The root cause of the vulnerability is a classic buffer overflow condition residing within the input parsing and memory management logic of affected IBM i services across versions 7.6, 7.5, 7.4, and 7.3. When the vulnerable component receives data from a remote source, it fails to perform adequate bounds checking on the size of the incoming payload relative to the allocated memory buffer.\nDuring the attack flow, a remote attacker crafts a specialized payload containing an excessive amount of data designed to exceed the fixed-size buffer allocated on the stack or heap. As the vulnerable application or operating system subsystem copies the oversized input into memory without proper validation, the incoming data overflows the boundaries of the destination buffer and overwrites adjacent memory regions, such as control variables, saved frame pointers, or return addresses.\nBecause the memory corruption corrupts critical execution structures, the affected process or subsystem encounters an unhandled exception or memory access violation upon attempting to process the corrupted state. This typically results in an immediate crash of the service or system component, precipitating a denial of service condition for dependent operations.\nNetwork exposure is inherent to this vulnerability if the affected IBM i services are reachable over the network. Authentication and privilege requirements depend on the specific daemon or interface handling the malformed input; however, the vulnerability allows remote attackers to initiate the attack sequence. The payload behavior is destructive to process stability, leading directly to a post-exploitation impact characterized solely by application or system unavailability requiring administrative intervention or service restarts to restore normal operations."
}