Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate to IBM i host
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DeliverySend crafted LPD print request
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ExploitTrigger off-by-one write in queue name parser
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ExecutionCorrupt adjacent memory
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ImpactCrash LPD service (DoS)
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Per the vendor description, exploitation requires both local access to the IBM i system and valid authentication credentials - the attacker must be an authenticated local user on the IBM i host. The vulnerable code path is the LPD queue name parser, meaning the LPD print service must be active and reachable. Exploitation is limited to a denial-of-service impact (A:L); there is no code execution, data exfiltration, or integrity violation. A critical data conflict exists: the vendor's CVSS vector specifies AV:N/PR:N (unauthenticated, network-reachable), directly contradicting 'local authenticated attacker' in the description - defenders must consult IBM's advisory to determine the actual access model before assessing real-world exposure. |
| Impact | The vendor-supplied CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L, score 5.3) is directly contradicted by the description, which explicitly states 'local authenticated attacker.' If the description is authoritative, the effective attack surface is substantially narrower than a CVSS Medium-network score implies - real-world exploitation requires both system access and valid credentials, not remote unauthenticated access. This discrepancy must be resolved with IBM before using the CVSS vector for prioritization. Impact is limited to availability (A:L, partial), with no confidentiality or integrity consequence. No EPSS data was provided; no KEV listing and no public exploit code exist, placing this in the 'low urgency' category for most organizations. IBM i deployments are predominantly in regulated industries (banking, manufacturing, government) where patch windows require planning - but the DoS-only scope and absence of active exploitation permit a measured response cadence. |
| Exploit ScenarioDerived | An attacker with local system access and valid credentials on an IBM i host sends a crafted print-queue request to the LPD parser containing a queue name of sufficient length to trigger the off-by-one write, corrupting adjacent memory. This causes the LPD service or a related daemon to crash, interrupting print services and potentially requiring an operator restart. No public exploit code exists at time of analysis, so exploitation currently requires manual knowledge of the parser's buffer boundary. |
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Alert meAnalysisAIv1 – Sep 04, 2026
Denial of service on IBM i versions 7.3 through 7.6 is achievable by exploiting an off-by-one write in the LPD (Line Printer Daemon) queue name parser, corrupting adjacent memory and crashing the affected service. The vendor description specifies a local authenticated attacker as the threat actor, yet IBM's own submitted CVSS vector (AV:N/AC:L/PR:N/UI:N) characterizes this as an unauthenticated network-reachable flaw - a direct contradiction that materially affects risk prioritization. No public exploit code or active exploitation (CISA KEV) has been identified at time of analysis.
RemediationAI
Apply the IBM-provided patch via the PTF (Program Temporary Fix) mechanism documented in the vendor advisory at https://www.ibm.com/support/pages/node/7285939. Exact PTF identifiers for each IBM i release (7.3, 7.4, 7.5, 7.6) are listed there and should be applied during the next available maintenance window. As a compensating control pending patching, organizations can disable or restrict access to the IBM i LPD service (port 515/TCP) using network-layer filtering or IBM i service configuration - this eliminates the network attack surface at the cost of losing legacy print-queue functionality for any LPD-dependent workflows. If LPD is not actively used, permanent disablement is advisable regardless of patch status.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
IBM i (formerly AS/400) is a proprietary midrange enterprise operating system. The affected component is its LPD implementation - the Line Printer Daemon protocol (historically TCP port 515) used for legacy network print-queue management. The root cause is CWE-787 (Out-of-Bounds Write): the queue name parser writes one byte past the end of a fixed-size buffer (an off-by-one condition), corrupting adjacent heap or stack memory. This class of vulnerability can destabilize the parsing process or the hosting daemon. The CPE string (cpe:2.3:a:ibm:i:*:*:*:*:*:*:*:*) covers all sub-versions of IBM i 7.3, 7.4, 7.5, and 7.6 without further version pinning. The 'Buffer Overflow' tag is a correct high-level characterization of CWE-787.
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Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Description specifies local authenticated attacker, so AV:L and PR:L; impact is availability-only (A:L), consistent with DoS via service crash.
Primary rating from Vendor (ibm).
CVSS VectorNVD
Lifecycle Timeline
1DescriptionNVD
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local authenticated attacker to cause a denial of service due to an off-by-one write in the LPD queue name parser.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
EUVD-2026-71470
GHSA-7m9p-5xg7-97w7
NVD
CVE.org
EPSS
Exploit-DB