How severe is CVE-2021-34801?

CVE-2021-34801 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2021-34801 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34801?

CVE-2021-34801 affects Valine.js Valine. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34801?

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

When was CVE-2021-34801 published?

CVE-2021-34801 was published on 2021-06-16 and last updated on 2026-06-17.

CVE-2021-34801

CVE-2021-34801 is a medium-severity vulnerability in Valine.js Valine with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Valine.js Valine
Published: 2021-06-16
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-34801?: CVE-2021-34801 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2021-34801 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34801?: CVE-2021-34801 affects Valine.js Valine. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34801?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-34801 published?: CVE-2021-34801 was published on 2021-06-16 and last updated on 2026-06-17.

References

https://github.com/xCss/Valine/issues/366

Affected products (1)

cpe:2.3:a:valine.js:valine:1.4.14:*:*:*:*:*:*:*

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