What is CVE-2021-34801?

CVE-2021-34801 is a medium-severity vulnerability in Valine.js Valine. CVSS score: 5.3/10. Published 2021-06-16.

How severe is CVE-2021-34801?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Valine.js Valine

CVE-2021-34801

Valine 1.4.14 allows remote attackers to cause a denial of service (application outage) by supplying a ua (aka User-Agent) value that only specifies the product and version.

Published 2021-06-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.017 (76.7th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 77th percentile — 76.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.017 · newest: 0.017 · change: 0.000

Affected products

Valine.js Valine — versions 1.4.14

References

github.com/xCss/Valine/issues/366 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-34801?: CVE-2021-34801 is a medium-severity vulnerability in Valine.js Valine. CVSS score: 5.3/10. Published 2021-06-16.
How severe is CVE-2021-34801?: Medium severity. CVSS v3 base score is 5.3 out of 10.