How severe is CVE-2021-3783?

CVE-2021-3783 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-2021-3783 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3783?

CVE-2021-3783 affects Yourls. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3783?

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

When was CVE-2021-3783 published?

CVE-2021-3783 was published on 2021-09-15 and last updated on 2026-06-17.

CVE-2021-3783

CVE-2021-3783 is a medium-severity vulnerability in Yourls 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% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Yourls
Published: 2021-09-15
Last modified: 2026-06-17

Description

yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Frequently asked questions

What is CVE-2021-3783?: yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
How severe is CVE-2021-3783?: CVE-2021-3783 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-2021-3783 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3783?: CVE-2021-3783 affects Yourls. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3783?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-3783 published?: CVE-2021-3783 was published on 2021-09-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:yourls:yourls:*:*:*:*:*:*:*:*

More vulnerabilities in Yourls

CVE-2019-14537 — Critical (CVSS 9.8): YOURLS through 1.7.3 is affected by a type juggling vulnerability in the api component that can result in login bypass.
CVE-2021-3734 — High (CVSS 8.8): yourls is vulnerable to Improper Restriction of Rendered UI Layers or Frames
CVE-2022-0088 — High (CVSS 7.4): Cross-Site Request Forgery (CSRF) in GitHub repository yourls/yourls prior to 1.8.3.
CVE-2021-3785 — Medium (CVSS 5.4): yourls is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE-2020-27388 — Medium (CVSS 5.4): Multiple Stored Cross Site Scripting (XSS) vulnerabilities exist in the YOURLS Admin Panel, Versions 1.5 - 1.7.10. An…
CVE-2011-3824 — Medium (CVSS 5.0): Your Own URL Shortener (YOURLS) 1.5 allows remote attackers to obtain sensitive information via a direct request to a…

All CVEs affecting Yourls →

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CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

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