CVE-2026-90647Network attack vector

TLS peer impersonation via incomplete certificate validation

Published Sep 12, 2026 · Updated Sep 12, 2026

Improper certificate validation in Kalkitech ASE2000 RTU Test Set 2.35 through 2.37 allows man-in-the-middle attackers to impersonate TLS peers. The IEC 60870-5-104 Task Mode TLS client accepts a certificate carrying multiple simultaneous validation faults instead of rejecting every certificate error. An attacker positioned on the network path can complete the TLS handshake as a trusted peer and read or modify protected communications.

CVSS severity7.4
High
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

Improper certificate validation in Kalkitech ASE2000 RTU Test Set 2.35 through 2.37 allows man-in-the-middle attackers to impersonate TLS peers. The IEC 60870-5-104 Task Mode TLS client accepts a certificate carrying multiple simultaneous validation faults instead of rejecting every certificate error. An attacker positioned on the network path can complete the TLS handshake as a trusted peer and read or modify protected communications.

The record

CVE
CVE-2026-90647
Published
Sep 12, 2026
Updated
Sep 12, 2026
Vendor
Kalkitech
Product
ASE2000 RTU Test Set
Classifications
CWE-295, CAPEC-475, CAPEC-459, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 12, 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=2.35 <2.38

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Kalkitech · ASE2000 RTU Test Setversion=2.35 <2.38

Published CVSS scores

7.4CISA ICS-CERTCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
CAPEC-475Signature Spoofing by Improper Validation
CAPEC-459Creating a Rogue Certification Authority Certificate
T1557Adversary-in-the-Middle

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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