How severe is CVE-2021-39420?

CVE-2021-39420 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-2021-39420 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39420?

CVE-2021-39420 affects Vfront. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39420?

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

When was CVE-2021-39420 published?

CVE-2021-39420 was published on 2021-11-08 and last updated on 2026-06-17.

CVE-2021-39420

CVE-2021-39420 is a medium-severity vulnerability in Vfront 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% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Vfront
Published: 2021-11-08
Last modified: 2026-06-17

Description

Multiple Cross Site Scripting (XSS) vulnerabilities exist in VFront 0.99.5 via the (1) s parameter in search_all.php and the (2) msg parameter in add.attach.php.

Frequently asked questions

What is CVE-2021-39420?: Multiple Cross Site Scripting (XSS) vulnerabilities exist in VFront 0.99.5 via the (1) s parameter in search_all.php and the (2) msg parameter in add.attach.php.
How severe is CVE-2021-39420?: CVE-2021-39420 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-2021-39420 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39420?: CVE-2021-39420 affects Vfront. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39420?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39420 published?: CVE-2021-39420 was published on 2021-11-08 and last updated on 2026-06-17.

References

https://sisl.lab.uic.edu/projects/chess/vfront0-99-5/

Affected products (1)

cpe:2.3:a:vfront:vfront:0.99.5:*:*:*:*:*:*:*

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CVE-2019-9839 — Medium (CVSS 6.1): VFront 0.99.5 has Reflected XSS via the admin/menu_registri.php descrizione_g parameter or the admin/sync_reg_tab.php…
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