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WeenyGenius CVE-2026-89177

| EUVDEUVD-2026-76004 HIGH
Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade') (CWE-757)
2026-09-11 twcert GHSA-35jr-c9gf-7v8m
8.7
CVSS 4.0 · Vendor: twcert
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Attack ChainAIDerived

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

  1. Access
    Gain adjacent network access
  2. Delivery
    Capture ZMTP Null mode traffic
  3. Exploit
    Identify management command frames
  4. Execution
    Replay or forge commands against target workstations
  5. Impact
    Disrupt classroom or exam operations

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Algorithm negotiation safety
Exploitation Conditions

Attacker must have adjacent network access - on the same LAN switch segment or WLAN as the WeenyGenius teacher console or managed student endpoints; the CVSS AV:A metric confirms this requirement. No authentication is required (PR:N) and no user interaction is needed (UI:N). The vulnerability is present whenever WeenyGenius is actively running and communicating, as ZMTP Null mode appears to be the default transport configuration. Exploitation is strictly limited by network adjacency: remote internet-based attackers cannot exploit this without first obtaining a foothold on the local school network.

Impact

The CVSS 4.0 score of 8.7 (AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H) correctly reflects full confidentiality, integrity, and availability impact but is bounded by the adjacent-network requirement. In a school setting this boundary is realistic to cross: students on shared classroom WiFi or wired lab ports are inherently adjacent. No EPSS data was provided and the vulnerability is absent from CISA KEV, so no evidence of active or widespread exploitation exists. The zero-complexity prerequisites (AC:L/AT:N/PR:N) make exploitation straightforward for anyone already on the right segment, removing practical barriers beyond network position. The integrity vector (VI:H via replay) arguably represents a higher operational risk than passive data capture alone, as forged commands can actively sabotage graded examinations or teacher-controlled sessions.

Exploit ScenarioDerived

A student connected to the classroom WiFi opens Wireshark and captures unencrypted ZMTP NULL frames exchanged between the teacher console and student workstations during a live session. The student identifies a 'lock workstation' command frame and replays it - without modification - against a peer's machine at a critical moment during an examination, locking them out. No credentials or custom exploit code are required beyond standard network capture utilities.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 11, 2026

WeenyGenius computer lab management software by Howyar Technologies transmits control commands over ZMTP Null mode - ZeroMQ's no-authentication, no-encryption transport - leaving all management traffic exposed on the local network. Unauthenticated adjacent-network attackers can passively capture plaintext session data or actively replay forged classroom commands to disrupt exams and lesson control. No public exploit has been identified and the vulnerability is not listed in CISA KEV, but the attack requires only standard network tooling and network adjacency.

RemediationAI

No vendor-released patch or fixed version number has been identified at time of analysis; consult the TWCERT advisory at https://www.twcert.org.tw/en/cp-139-11200-ffc3c-2.html for updated vendor guidance. As compensating controls pending a software fix: isolate WeenyGenius management traffic on a dedicated VLAN inaccessible to student or guest devices, which eliminates the adjacent-network position required for exploitation (trade-off: requires managed switching infrastructure); enforce WPA3 with PMF (Protected Management Frames) on any wireless segment used by lab clients to prevent passive capture of ZMTP frames over WiFi (trade-off: does not protect wired segments); and restrict ZeroMQ port access via host-based or perimeter firewall rules to permit connections only from known teacher-console IP addresses, reducing the replay attack surface (trade-off: does not encrypt traffic, only limits who can connect).

Affected VersionsENISA

WeenyGenius 0 ≤12.2.031

Affected Packages

euvd weenygenius 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

WeenyGenius (cpe:2.3:a:howyar:weenygenius) uses ZeroMQ messaging as its inter-process transport layer. ZeroMQ's ZMTP (ZeroMQ Transport Protocol) supports three security mechanisms: NULL (no auth, no encryption), PLAIN (cleartext credential exchange), and CURVE (elliptic-curve authenticated encryption). The product selects the NULL mechanism, which maps directly to CWE-757 (Selection of Less-Secure Algorithm During Negotiation): when a system negotiates the weakest available option by default, all traffic is observable and injectable without any cryptographic barrier. Because ZMTP carries structured command frames (lock screen, end session, transfer files, etc.), passive capture exposes operational details and replay requires only retransmitting a captured packet without modification.

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Severity by source

Vendor (twcert) PRIMARY 8.7 HIGH
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
vuln.today AI 8.8 HIGH

Adjacent-network position required (AV:A); no authentication or interaction needed; full triad impact from eavesdropping (C:H) and unauthenticated command replay (I:H/A:H); no scope change.

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

Primary rating from Vendor (twcert).

CVSS VectorVendor: twcert

Attack Vector
Adjacent
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

WeenyGenius, a computer lab management system by Howyar Technologies, has a Use of Insecure Protocol vulnerability. Due to the reliance on ZMTP Null mode, unauthenticated attackers on the same network can capture packets to leak transmitted data, or perform replay attacks with forged commands to disrupt classroom operations.

Executive ViewAI

Why It Matters

WeenyGenius classroom management software by Howyar Technologies transmits all control commands and session data in plaintext over an unauthenticated network protocol, exposing educational institutions to exam disruption, lesson control hijacking, and sensitive classroom data interception from any device on the adjacent network. Organizations using this product face immediate risk to academic integrity and operational continuity with no vendor patch currently available.

Business Impact: High
Compensating Controls

Isolate lab management network on dedicated VLAN with strict firewall rules limiting access to authorized administrative subnets only; deploy network intrusion detection tuned to ZMTP Null mode traffic patterns to detect replay attacks and unauthorized commands; restrict physical and logical access to lab management consoles to credentialed staff via hardened jump hosts; implement comprehensive command logging with real-time alerting on anomalous classroom control sequences; disable remote lab management capabilities until encryption can be deployed; monitor for behavioral indicators of active exploitation (unexpected exam cancellations, lesson plan modifications, session terminations).

Threat Intelligence Overview

EPSS Score
0.2%
Top 86% exploitable
Prevalence
Low
niche Taiwanese education-sector lab management product
Social Media
2
Sightings
Data Quality
6 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 HIGH
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Scheduled
Exploitation
None
System Exposure· derived
Controlled
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +44
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

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

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