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Vulnerability record · CVE-2021-34540 · published 11 June 2021

CVE-2021-34540: Advantech webaccess cross-site scripting vulnerability

Advantech · Webaccess

Advantech WebAccess 8.4.2 and 8.4.4 allows XSS via the username column of the bwRoot.asp page of WADashboard.

6.1 CVSS 3.1 Medium EPSS 0.87% · top 42.9% CWE-79 · Cross-site scripting
6.1CVSS 3.1 base score, v2 4.3
0.87%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

Advantech WebAccess 8.4.2 and 8.4.4 allows XSS via the username column of the bwRoot.asp page of WADashboard.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/ethancsyang/CveProject/tree/main/CVE-2021-34540 ExploitThird Party Advisory
https://www.advantech.com/support Vendor Advisory
https://github.com/ethancsyang/CveProject/tree/main/CVE-2021-34540 ExploitThird Party Advisory
https://www.advantech.com/support Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2014-9208Advantech webaccess memory buffer overflow vulnerabilityMultiple stack-based buffer overflows in unspecified DLL files in Advantech WebAccess before 8.0.1 allow remote attackers to execute arbitrary code v…EPSS 9.3%9.8CVE-2021-33023Advantech webaccess heap-based buffer overflow vulnerabilityAdvantech WebAccess versions 9.02 and prior are vulnerable to a heap-based buffer overflow, which may allow an attacker to remotely execute code.EPSS 2.3%9.8CVE-2021-38389Advantech webaccess stack-based buffer overflow vulnerabilityAdvantech WebAccess versions 9.02 and prior are vulnerable to a stack-based buffer overflow, which may allow an attacker to remotely execute code.EPSS 10%9.8CVE-2021-38408Advantech webaccess stack-based buffer overflow vulnerabilityA stack-based buffer overflow vulnerability in Advantech WebAccess Versions 9.02 and prior caused by a lack of proper validation of the length of use…EPSS 12%9.8CVE-2020-12019Advantech webaccess stack-based buffer overflow vulnerabilityWebAccess Node Version 8.4.4 and prior is vulnerable to a stack-based buffer overflow, which may allow an attacker to remotely execute arbitrary code.EPSS 2.2%9.8CVE-2020-10638Advantech webaccess heap-based buffer overflow vulnerabilityAdvantech WebAccess Node, Version 8.4.4 and prior, Version 9.0.0. Multiple heap-based buffer overflow vulnerabilities exist caused by a lack of prope…EPSS 7.1%9.8CVE-2020-12002Advantech webaccess stack-based buffer overflow vulnerabilityAdvantech WebAccess Node, Version 8.4.4 and prior, Version 9.0.0. Multiple stack-based buffer overflow vulnerabilities exist caused by a lack of prop…EPSS 9.1%9.8CVE-2020-12006Advantech webaccess relative path traversal vulnerabilityAdvantech WebAccess Node, Version 8.4.4 and prior, Version 9.0.0. Multiple relative path traversal vulnerabilities exist that may allow a low privile…EPSS 3.7%

Source: NIST National Vulnerability Database (record CVE-2021-34540), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.