How severe is CVE-2020-36321?

CVE-2020-36321 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2020-36321 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-2020-36321?

CVE-2020-36321 primarily affects Vaadin Flow. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-36321?

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

When was CVE-2020-36321 published?

CVE-2020-36321 was published on 2021-04-23 and last updated on 2026-06-17.

CVE-2020-36321

CVE-2020-36321 is a medium-severity vulnerability in Vaadin Flow with a CVSS 3.x base score of 5.9. 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-22.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 5.0
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Vaadin Flow
Published: 2021-04-23
Last modified: 2026-06-17

Description

Improper URL validation in development mode handler in com.vaadin:flow-server versions 2.0.0 through 2.4.1 (Vaadin 14.0.0 through 14.4.2), and 3.0 prior to 5.0 (Vaadin 15 prior to 18) allows attacker to request arbitrary files stored outside of intended frontend resources folder.

Frequently asked questions

What is CVE-2020-36321?: Improper URL validation in development mode handler in com.vaadin:flow-server versions 2.0.0 through 2.4.1 (Vaadin 14.0.0 through 14.4.2), and 3.0 prior to 5.0 (Vaadin 15 prior to 18) allows attacker to request arbitrary files stored outside of intended frontend resources folder.
How severe is CVE-2020-36321?: CVE-2020-36321 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-36321 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-2020-36321?: CVE-2020-36321 primarily affects Vaadin Flow. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-36321?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-36321 published?: CVE-2020-36321 was published on 2021-04-23 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:vaadin:flow:*:*:*:*:*:*:*:*
cpe:2.3:a:vaadin:vaadin:*:*:*:*:*:*:*:*

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