CVE-2026-18251Network attack vector

Information disclosure via unchecked WebSocket origins

Published Sep 14, 2026 · Updated Sep 14, 2026

Missing WebSocket origin validation in IBMi 7.3 through 7.6 allows remote attackers to obtain sensitive information. Navigator accepts a browser-initiated WebSocket handshake without verifying that the Origin header belongs to a trusted site. A user must visit attacker-controlled content, which can open a cross-origin WebSocket to the Navigator service and expose data available through that connection.

CVSS severity4.3
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing WebSocket origin validation in IBMi 7.3 through 7.6 allows remote attackers to obtain sensitive information. Navigator accepts a browser-initiated WebSocket handshake without verifying that the Origin header belongs to a trusted site. A user must visit attacker-controlled content, which can open a cross-origin WebSocket to the Navigator service and expose data available through that connection.

The record

CVE
CVE-2026-18251
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
IBM
Product
IBM i
Classifications
CWE-1385, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.3
  2. Affected versionversion=7.4
  3. Affected versionversion=7.5
  4. Affected versionversion=7.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · IBM iversion=7.3; version=7.4; version=7.5; version=7.6

Published CVSS scores

4.3IBMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1385Missing Origin Validation in WebSockets
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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