What is CVE-2026-66300?

CVE-2026-66300 is a medium-severity vulnerability in Snomed International Snowstorm, classified under Cross-site Scripting. CVSS score: 5.0/10. Published 2026-08-04.

How severe is CVE-2026-66300?

Medium severity. CVSS v3 base score is 5.0 out of 10.

XSS in Snomed International Snowstorm

CVE-2026-66300

SNOMED International Snowstorm contains a reflected XSS vulnerability within the "Web Route" redirection functionality. An attacker can inject arbitrary JavaScript which will execute upon a target user navigating to a crafted, malicious link. Fixed in 10.12.2 and 10.9.3.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-08-04 · last modified 2026-10-24.

CVSS v3 metric

CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.003 (25.1th percentile), scored 2026-11-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Snomed International Snowstorm — versions 7.0.0, 10.12.2, 10.9.3

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

9119a7d8-5eab-497f-8521-727c672e3725 (patch)
9119a7d8-5eab-497f-8521-727c672e3725 (patch)
9119a7d8-5eab-497f-8521-727c672e3725 (vdb-entry)
9119a7d8-5eab-497f-8521-727c672e3725 (third-party-advisory)

Frequently asked questions

What is CVE-2026-66300?: CVE-2026-66300 is a medium-severity vulnerability in Snomed International Snowstorm, classified under Cross-site Scripting. CVSS score: 5.0/10. Published 2026-08-04.
How severe is CVE-2026-66300?: Medium severity. CVSS v3 base score is 5.0 out of 10.