What is CVE-2017-10840?

CVE-2017-10840 is a medium-severity vulnerability in K5n.us Webcalendar, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2017-08-29.

How severe is CVE-2017-10840?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in K5n.us Webcalendar

CVE-2017-10840

Cross-site scripting vulnerability in WebCalendar 1.2.7 and earlier allows an attacker to inject arbitrary web script or HTML via unspecified vectors.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2017-08-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.009 (59.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 59.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

K5n.us Webcalendar — versions 1.2.7 and earlier
Webcalendar Project — versions 1.2.7

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

jvn.jp/en/jp/JVN23340457/index.html (VDB Entry, Third Party Advisory, third-party-advisory)
github.com/craigk5n/webcalendar/releases/tag/v1.2.8 (Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2017-10840?: CVE-2017-10840 is a medium-severity vulnerability in K5n.us Webcalendar, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2017-08-29.
How severe is CVE-2017-10840?: Medium severity. CVSS v3 base score is 6.1 out of 10.