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Bascontrol20 EUVDEUVD-2025-209395

| CVE-2025-13926 CRITICAL
Reliance on Untrusted Inputs in a Security Decision (CWE-807)
2026-04-09 icscert
9.3
CVSS 4.0 · Vendor: icscert
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Trusted input validation
Impact

CVSS 9.3 reflects unauthenticated network access enabling packet forgery via sniffed credentials. CWE-807 (reliance on unverified network data) compounds exposure for ICS environments where BASC 20T controls critical infrastructure. No authentication required. Blast radius spans all networked instances; elevated observed exploitation activity signals real-world targeting.

Exploit ScenarioDerived

Attacker captures unencrypted BASC 20T network traffic, extracts authentication material, and forges control packets over the network to execute arbitrary commands on the device. No authentication bypass needed; AV:N/PR:N enables direct exploitation.

Monitor Track and reassess. Why: Vendor states no customer action required.
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Apr 09, 2026

Session token exposure in Contemporary Controls BASControl20 3.1 building automation controller enables unauthenticated remote attackers to forge authenticated requests via network traffic interception. Exploitation requires attacker ability to sniff network traffic containing authentication credentials, which can then be replayed to execute arbitrary commands with full system privileges. Classified as CWE-807 (untrusted input reliance), this vulnerability permits complete compromise of controller confidentiality, integrity, and availability without user interaction. No public exploit identified at time of analysis.

RemediationAI

No vendor-released patch identified at time of analysis. Contact Contemporary Controls technical support directly via https://www.ccontrols.com/support/contacttech.htm for remediation guidance specific to BASControl20 3.1 deployments. Until patches are available, implement network segmentation to isolate BASControl20 devices from untrusted networks, deploy encrypted communication channels (VPN/TLS) to prevent credential interception, and restrict network access to the controller using firewall rules permitting only authenticated administrative hosts. Monitor CISA advisory ICSA-26-099-01 for updates: https://www.cisa.gov/news-events/ics-advisories/icsa-26-099-01. Consider disabling remote access features if operationally feasible until vendor provides cryptographically secure session management.

Affected VersionsENISA

BASControl20 3.1

Affected Packages

euvd bascontrol20 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

Root cause is inadequate session management allowing credential replay attacks (CWE-807). Authentication tokens transmitted over the network lack cryptographic binding or replay protection mechanisms, permitting passive network interception followed by credential reuse. CVSS:4.0 vector confirms unauthenticated network attack (PR:N, AV:N) with no complexity barriers (AC:L, AT:N), yielding high impact across all CIA dimensions for vulnerable component.

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Severity by source

Vendor (icscert) PRIMARY 9.3 CRITICAL
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (icscert) · only source for this CVE.

CVSS VectorVendor: icscert

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

An attacker could use data obtained by sniffing the network traffic to forge packets in order to make arbitrary requests to Contemporary Controls BASC 20T.

Executive ViewAI

Why It Matters

Contemporary Controls BASControl20 3.1 building automation controllers contain a critical session token exposure vulnerability that allows unauthenticated attackers with network access to intercept credentials and execute arbitrary commands with full system privileges, potentially compromising HVAC, lighting, and facility controls across your infrastructure. This affects any organization using this controller model in networked environments and requires immediate network isolation to prevent compromise of critical building systems.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Implement strict network segmentation-isolate BASControl20 devices on dedicated VLAN with firewall rules restricting inbound/outbound traffic to essential management IPs only; (2) Deploy network intrusion detection (IDS) monitoring on BASControl20 network segments to detect credential sniffing and authentication replay; (3) Enforce encrypted management channels (TLS 1.2+) for all controller communications; (4) Implement network access controls (802.1X) if controller supports authenticated port access; (5) Disable remote management access until patch is available; (6) Monitor controller logs for unexplained command execution or privilege escalation; (7) Maintain ready replacement hardware pending vendor patch availability.

Threat Intelligence Overview

EPSS Score
0.1%
Top 78% exploitable
Threat Intel
1
1 source
Social Media
1
Sightings
Data Quality
8 sources
Confidence: High

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 CRITICAL
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat Yes
Deciding rule
Vendor states no customer action required
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
Out-of-Cycle
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
Very High
Technical Impact
Total

Priority Score

56
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +46
PoC: 0
Weaponized: 0
Threat intel: +10
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Threat IntelligenceMISP

CISA Advisories
Sources: CISA (public domain)

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