Denial of service in Valine

published 2021-06-16 5y ago modified 2026-06-17 4mo ago also GHSA-p2c4-gxp4-j3xp , EUVD-2021-1366

cvss: 5.3; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.7%; EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits: 0; none known

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.

Is CVE-2021-34801 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

1.72% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

github.com https://github.com/xCss/Valine/issues/366 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem	package	affected	fixed in
npm	valine	<=1.4.14	no fix listed

Classification

Weakness

CWE-94 Improper Control of Generation of Code

References

github.com /xCss/Valine/issues/366
web, exploit, issue-tracking, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2021-34801
advisory
github.com /xCss/Valine
package

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.