How severe is CVE-2020-18657?

CVE-2020-18657 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-2020-18657 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-18657?

CVE-2020-18657 affects Get-simple Getsimplecms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-18657?

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

When was CVE-2020-18657 published?

CVE-2020-18657 was published on 2021-06-23 and last updated on 2026-06-17.

CVE-2020-18657

CVE-2020-18657 is a medium-severity vulnerability in Get-simple Getsimplecms 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% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Get-simple Getsimplecms
Published: 2021-06-23
Last modified: 2026-06-17

Description

Cross Site Scripting (XSS) vulnerability in GetSimpleCMS <= 3.3.15 in admin/changedata.php via the redirect_url parameter and the headers_sent function.

Frequently asked questions

What is CVE-2020-18657?: Cross Site Scripting (XSS) vulnerability in GetSimpleCMS <= 3.3.15 in admin/changedata.php via the redirect_url parameter and the headers_sent function.
How severe is CVE-2020-18657?: CVE-2020-18657 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-2020-18657 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-18657?: CVE-2020-18657 affects Get-simple Getsimplecms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-18657?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-18657 published?: CVE-2020-18657 was published on 2021-06-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:get-simple:getsimplecms:*:*:*:*:*:*:*:*

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