How severe is CVE-2021-40921?

CVE-2021-40921 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-2021-40921 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40921?

CVE-2021-40921 affects Detector Project Detector. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40921?

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

When was CVE-2021-40921 published?

CVE-2021-40921 was published on 2021-10-01 and last updated on 2026-06-17.

CVE-2021-40921

CVE-2021-40921 is a medium-severity vulnerability in Detector Project Detector 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% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Detector Project Detector
Published: 2021-10-01
Last modified: 2026-06-17

Description

Cross-site scripting (XSS) vulnerability in _contactform.inc.php in Detector 0.8.5 and below version allows remote attackers to inject arbitrary web script or HTML via the cid parameter.

Frequently asked questions

What is CVE-2021-40921?: Cross-site scripting (XSS) vulnerability in _contactform.inc.php in Detector 0.8.5 and below version allows remote attackers to inject arbitrary web script or HTML via the cid parameter.
How severe is CVE-2021-40921?: CVE-2021-40921 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-2021-40921 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40921?: CVE-2021-40921 affects Detector Project Detector. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40921?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-40921 published?: CVE-2021-40921 was published on 2021-10-01 and last updated on 2026-06-17.

References

https://github.com/dmolsen/Detector/issues/35

Affected products (1)

cpe:2.3:a:detector_project:detector:*:*:*:*:*:*:*:*

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