CVE-2026-66300: SNOMED International Snowstorm · Cross-site Scripting
Affects SNOMED International SnowstormSource CVE Database V5
Not known to be exploited · CVSS 5.0 Medium : upgrade to 10.12.2 when convenient.
Data as of 2 Nov 2026, 22:58 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 10.12.2, 10.9.3
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:LExploitation evidence
Disclosed: evidence found.
CVE published 4 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.
What to do
Upgrade Snowstorm to 10.12.2; ihtsdo/snowstorm to 10.12.2 or 10.9.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| SNOMED InternationalSnowstorm | Affected
| Fixed in
|
GitHubihtsdo/snowstormpkg:github/ihtsdo/snowstormOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
The vulnerability is fixed in Snowstorm versions 10.12.2 and 10.9.3. Users and administrators should upgrade to these or later versions to remediate the issue. No other vendor advisories or temporary mitigations are provided. Patch status is confirmed by the vendor's fixed versions.
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.
References
- github.com/IHTSDO/snowstorm/commit/575b555695811110dafe2fcea7dd2fd7e4bcee39 (opens in a new tab)
- github.com/IHTSDO/snowstorm/commit/b8061add427c930b3030549e77aa23ec5957ceb6 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-66300 (opens in a new tab)
- raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-212-01.json (opens in a new tab)