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IBM i CVE-2026-17068

| EUVDEUVD-2026-103141 LOW
Improper Authorization (CWE-285)
2026-10-16 ibm GHSA-xcpc-99c5-x72g
3.3
CVSS 3.1 · NVD
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Authenticate with low privileges on IBM i
  2. Delivery
    Target misenforced NFS export version flag
  3. Exploit
    Mount export using restricted NFS version
  4. Execution
    Bypass intended version restriction
  5. Impact
    Access or alter exported data

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization verification
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the IBM i NFS server to be configured with version-restricted exports (the 'export version flag' must be in use to be bypassed); on default systems without NFS exports or without version restrictions, there is nothing to bypass. The attacker must already hold an authenticated low-privilege session (CVSS PR:L), and the description further limits this to a 'local attacker,' implying an on-host or local foothold rather than a fully remote unauthenticated attacker despite the AV:N metric. Limiting factors: NFS must be enabled and exporting data with intended version restrictions, valid low-level credentials are needed, and impact is confined to bypassing version controls (C:L/I:L, no availability loss).

Impact

This is a moderate-severity authorization flaw (CVSS 5.4) with conflicting signals that temper real-world urgency. The CVSS vector supplied by IBM (AV:N/AC:L/PR:L/UI:N) describes a low-complexity, network-reachable attack requiring only low privileges, yielding limited confidentiality and integrity impact (C:L/I:L) and no availability impact. However, the description explicitly characterizes the actor as a 'local attacker,' which directly conflicts with the AV:N (network) metric - verify the true attack vector with IBM, as this materially changes exposure. There is no EPSS score, no CISA KEV listing, and no public POC provided, so exploitation is not confirmed or observed. SSVC-style reasoning: exploitation is 'none' (no evidence of active use), the flaw is likely not automatable (it is an authorization-enforcement bug requiring an authenticated session and NFS-specific conditions), and technical impact is 'partial' (bypasses NFS version restrictions rather than granting full compromise). Net assessment: this is a real but mid-tier priority - patch in normal cycles rather than emergency. It is not a high-CVSS-but-trivial issue, but neither does it show the hallmarks (KEV/POC/high EPSS) of imminent mass exploitation.

Exploit ScenarioDerived

An attacker with low-level authenticated access to an IBM i system (7.3-7.6) manipulates NFS export handling so that the export version flag is not properly enforced, allowing them to mount or access an NFS export using a protocol version the administrator intended to restrict. No public exploit code is identified at time of analysis, and the low attack complexity means a knowledgeable insider or foothold-holder could attempt this without special timing or race conditions.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 16, 2026

IBM i versions 7.3 through 7.6 contain an improper authorization flaw in the NFS server that allows a local, authenticated low-privilege attacker to bypass configured NFS export version restrictions. The vulnerability requires the NFS server to be configured with version-restricted exports to have any impact, and exploitation is limited to bypassing version controls with low confidentiality and integrity impact. This moderate-severity issue (assessed CVSS 5.4, AV:L) has no public exploit identified at time of analysis, and a vendor patch is available.

RemediationAI

Apply the vendor-released patch for IBM i through the official advisory at https://www.ibm.com/support/pages/node/7292423. No specific patched version number is provided in the available data, so consult the advisory for the exact PTF or release update. If patching is not immediately possible, mitigate by disabling the NFS server if it is not required (side effect: loss of NFS file sharing), restricting NFS exports to trusted hosts via export access lists (reduces exposure but does not fix the bypass), or auditing version-restricted exports to ensure no unauthorized version negotiation occurs. Because exploitation requires authenticated local access, limiting local user privileges and monitoring for anomalous NFS version requests can further reduce risk.

Affected VersionsENISA

i 7.4
i 7.6
i 7.5
i 7.3

Affected Packages

euvd i no fix

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

The flaw resides in the IBM i NFS server's handling of the export version flag, which is intended to restrict which NFS protocol versions (e.g., v2, v3, v4) are permitted for a given export. CWE-285 (Improper Authorization) indicates that the server fails to correctly enforce this authorization check, allowing a client to negotiate a disallowed version. NFS is a widely used file-sharing protocol; on IBM i, NFS exports are configured per file system and version restrictions are a security control. The CPE cpe:2.3:a:ibm:i:*:*:*:*:*:*:*:* identifies all IBM i releases as potentially affected. While the CVE record lists a network vector (AV:N), the independent assessment and the description ('local attacker') indicate that exploitation requires a local foothold and valid low-privilege credentials, with impact limited to bypassing version enforcement (C:L/I:L, no availability loss).

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Severity by source

Vendor (ibm) PRIMARY MEDIUM
NVD 3.3 LOW
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
vuln.today AI 4.4 MEDIUM

Description states a local attacker, so AV:L over the vendor's AV:N; PR:L for the required authenticated session; limited C/I impact from version-restriction bypass and no availability effect.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (ibm).

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

Lifecycle Timeline

2
Severity Changed
Oct 23, 2026 - 16:07 NVD
MEDIUM LOW
CVSS changed
Oct 23, 2026 - 16:07 NVD
5.4 (MEDIUM) 3.3 (LOW)

DescriptionNVD

IBM i 7.3, 7.4, 7.5, and 7.6 could allow a local attacker to bypass NFS version restrictions due to improper enforcement of the export version flag.

Threat Intelligence Overview

EPSS Score
0.1%
Top 97% exploitable
Prevalence
Medium
IBM i is a common enterprise midrange OS, concentrated in finance/retail, not universal
Social Media
1
Sightings
Data Quality
5 sources
Confidence: Medium

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.

SignalValue
Severity LOW
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
LOW severity (CVSS 0.1-3.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

16
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +16
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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