CVE-2021-33023
highpriority · track · 40EPSS 0.023 · 84 %ileEUUSEPSS · scored 2026-10-27
Advantech WebAccess versions 9.02 and prior are vulnerable to a heap-based buffer overflow, which may allow an attacker to remotely execute code.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedWebAccesscisa_csaf_ot
In order to address the heap-based buffer overflow vulnerability, Advantech recommends users directly add the remote access code to avoid being attacked by unknown requests. This is the remote access code established during installation of the Advantech WebAccess SCADA software (SCADA node, project node, or OPC Service) on the OPC Server computer. The access code you enter here must match the remote access code established during installation on the OPC Server. This prevents unauthorized users from accessing the OPC Server data using the Advantech WebAccess SCADA OPC Service.
- MitigationWebAccesscisa_csaf_ot
If you have forgotten the remote access code using during software installation on the OPC Server node, you have two options:
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.5–9.8
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (4)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- ICSA-21-285-02Advantech WebAccess2021-10-12icsa · cisa_csaf_otUS
Successful exploitation of these vulnerabilities could allow an attacker to gain remote code execution.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7)
External citations — patches, advisories, analysis.
- https://nvd.nist.gov/vuln/detail/CVE-2021-33023cnnvd
- https://us-cert.cisa.gov/ics/advisories/icsa-21-285-02cnnvd
- https://www.auscert.org.au/bulletins/ESB-2021.3440cnnvd
- https://www.cybersecurity-help.cz/vdb/SB2021101312cnnvd
- https://www.zerodayinitiative.com/advisories/ZDI-22-257/cnnvd
- https://us-cert.cisa.gov/ics/advisories/icsa-21-285-02enisa_euvd
- https://us-cert.cisa.gov/ics/advisories/icsa-21-285-02MitigationThird Party AdvisoryUS Government Resourcenvd
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