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Webaccess CVE-2019-3951

CRITICAL
Stack-based Buffer Overflow (CWE-121)
2019-12-12 vulnreport@tenable.com
9.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK

1 technique across 1 tactic: Execution

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

Impact

CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.
No patch listed yet 3.6% exploitation probability (EPSS)

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AnalysisAI

Advantech WebAccess before 8.4.3 allows unauthenticated remote attackers to execute arbitrary code or cause a denial of service (memory corruption) due to a stack-based buffer overflow when handling. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-121. Advantech WebAccess before 8.4.3 allows unauthenticated remote attackers to execute arbitrary code or cause a denial of service (memory corruption) due to a stack-based buffer overflow when handling IOCTL 70533 RPC messages. Affected products include: Advantech Webaccess. Version information: before 8.4.3.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

DescriptionNVD

Advantech WebAccess before 8.4.3 allows unauthenticated remote attackers to execute arbitrary code or cause a denial of service (memory corruption) due to a stack-based buffer overflow when handling IOCTL 70533 RPC messages.

Threat Intelligence Overview

EPSS Score
3.6%
Top 12% exploitable
Exploit
POC
Public exploit code exists
Data Quality
2 sources
Confidence: Low

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 Yes
EPSS 3.6%
Patch available No
Active threat No
Deciding rule
CRITICAL severity + public POC available
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· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

73
Low Medium High Critical
KEV: 0
EPSS: +4
CVSS: +49
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:advantech:webaccess:*:*:*:*:*:*:*:*
CVE-2016-0854 CRITICAL POC
9.8 Jan 15

Unrestricted file upload vulnerability in the uploadImageCommon function in the UploadAjaxAction script in the WebAccess

CVE-2016-0856 CRITICAL
9.8 Jan 15

Multiple stack-based buffer overflows in Advantech WebAccess before 8.1 allow remote attackers to execute arbitrary code

CVE-2014-9208 CRITICAL POC
10.0 Sep 11

Multiple stack-based buffer overflows in unspecified DLL files in Advantech WebAccess before 8.0.1 allow remote attacker

CVE-2017-14016 MEDIUM POC
6.3 Nov 06

A Stack-based Buffer Overflow issue was discovered in Advantech WebAccess versions prior to V8.2_20170817. Rated medium

CVE-2016-5810 MEDIUM POC
4.9 May 02

upAdminPg.asp in Advantech WebAccess before 8.1_20160519 allows remote authenticated administrators to obtain sensitive

CVE-2019-3975 CRITICAL POC
9.8 Sep 10

Stack-based buffer overflow in Advantech WebAccess/SCADA 8.4.1 allows a remote, unauthenticated attacker to execute arbi

CVE-2019-3954 CRITICAL POC
9.8 Jun 19

Stack-based buffer overflow in Advantech WebAccess/SCADA 8.4.0 allows a remote, unauthenticated attacker to execute arbi

CVE-2019-3953 CRITICAL POC
9.8 Jun 18

Stack-based buffer overflow in Advantech WebAccess/SCADA 8.4.0 allows a remote, unauthenticated attacker to execute arbi

CVE-2018-6911 CRITICAL POC
9.8 Feb 13

The VBWinExec function in Node\AspVBObj.dll in Advantech WebAccess 8.3.0 allows remote attackers to execute arbitrary OS

CVE-2018-15704 HIGH POC
8.8 Oct 22

Advantech WebAccess 8.3.2 and below is vulnerable to a stack buffer overflow vulnerability. Rated high severity (CVSS 8.

CVE-2019-3941 HIGH POC
7.5 Apr 09

Advantech WebAccess 8.3.4 allows unauthenticated, remote attackers to delete arbitrary files via IOCTL 10005 RPC. Rated

CVE-2017-12698 CRITICAL
9.8 Aug 30

An Improper Authentication issue was discovered in Advantech WebAccess versions prior to V8.2_20170817. Rated critical s

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