How severe is CVE-2021-21937?

CVE-2021-21937 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-21937 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21937?

CVE-2021-21937 affects Advantech R-seenet. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21937?

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

When was CVE-2021-21937 published?

CVE-2021-21937 was published on 2021-12-22 and last updated on 2026-06-17.

CVE-2021-21937

CVE-2021-21937 is a medium-severity vulnerability in Advantech R-seenet with a CVSS 3.x base score of 6.5. 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-89.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-89
Affected product: Advantech R-seenet
Published: 2021-12-22
Last modified: 2026-06-17

Description

A specially-crafted HTTP request can lead to SQL injection. An attacker can make authenticated HTTP requests to trigger this vulnerability at ‘host_alt_filter’ parameter. This can be done as any authenticated user or through cross-site request forgery.

Frequently asked questions

What is CVE-2021-21937?: A specially-crafted HTTP request can lead to SQL injection. An attacker can make authenticated HTTP requests to trigger this vulnerability at ‘host_alt_filter’ parameter. This can be done as any authenticated user or through cross-site request forgery.
How severe is CVE-2021-21937?: CVE-2021-21937 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-21937 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21937?: CVE-2021-21937 affects Advantech R-seenet. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21937?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21937 published?: CVE-2021-21937 was published on 2021-12-22 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1366

Affected products (1)

cpe:2.3:a:advantech:r-seenet:2.4.15:*:*:*:*:*:*:*

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