How severe is CVE-2021-20725?

CVE-2021-20725 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-2021-20725 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20725?

CVE-2021-20725 affects Calendar01 Project Calendar01. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20725?

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

When was CVE-2021-20725 published?

CVE-2021-20725 was published on 2021-05-24 and last updated on 2026-06-17.

CVE-2021-20725

CVE-2021-20725 is a medium-severity vulnerability in Calendar01 Project Calendar01 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% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Calendar01 Project Calendar01
Published: 2021-05-24
Last modified: 2026-06-17

Description

Reflected cross-site scripting vulnerability in the admin page of [Calendar01] free edition ver1.0.1 and earlier allows a remote attacker to inject an arbitrary script via unspecified vectors.

Frequently asked questions

What is CVE-2021-20725?: Reflected cross-site scripting vulnerability in the admin page of [Calendar01] free edition ver1.0.1 and earlier allows a remote attacker to inject an arbitrary script via unspecified vectors.
How severe is CVE-2021-20725?: CVE-2021-20725 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-2021-20725 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20725?: CVE-2021-20725 affects Calendar01 Project Calendar01. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20725?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-20725 published?: CVE-2021-20725 was published on 2021-05-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:calendar01_project:calendar01:*:*:*:*:free:*:*:*

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CVE-2020-5616 — Critical (CVSS 9.8): [Calendar01], [Calendar02], [PKOBO-News01], [PKOBO-vote01], [Telop01], [Gallery01], [CalendarForm01], and [Link01]…
CVE-2020-5615 — High (CVSS 8.8): Cross-site request forgery (CSRF) vulnerability in [Calendar01] free edition ver1.0.0 and [Calendar02] free edition…

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