How severe is CVE-2021-27436?

CVE-2021-27436 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-27436 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27436?

CVE-2021-27436 affects Advantech Webaccess/scada. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27436?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-27436 published?

CVE-2021-27436 was published on 2021-03-18 and last updated on 2026-06-17.

CVE-2021-27436

CVE-2021-27436 is a medium-severity vulnerability in Advantech Webaccess/scada with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Advantech Webaccess/scada
Published: 2021-03-18
Last modified: 2026-06-17

Description

WebAccess/SCADA Versions 9.0 and prior is vulnerable to cross-site scripting, which may allow an attacker to send malicious JavaScript code to an unsuspecting user, which could result in hijacking of the user’s cookie/session tokens, redirecting the user to a malicious webpage and performing unintended browser actions.

Frequently asked questions

What is CVE-2021-27436?: WebAccess/SCADA Versions 9.0 and prior is vulnerable to cross-site scripting, which may allow an attacker to send malicious JavaScript code to an unsuspecting user, which could result in hijacking of the user’s cookie/session tokens, redirecting the user to a malicious webpage and performing unintended browser actions.
How severe is CVE-2021-27436?: CVE-2021-27436 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-27436 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27436?: CVE-2021-27436 affects Advantech Webaccess/scada. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27436?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-27436 published?: CVE-2021-27436 was published on 2021-03-18 and last updated on 2026-06-17.

References

https://us-cert.cisa.gov/ics/advisories/icsa-21-075-01

Affected products (1)

cpe:2.3:a:advantech:webaccess\/scada:*:*:*:*:*:*:*:*

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