CVE-2026-66300

MEDIUMPre-NVD 5.05.0—
EchelonGraph scoreHIGH confidence

Score 5.0 from GitHub Security Advisory (severity: LOW) published 2026-08-04. a secondary CVSS source baseline 5.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.0Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.0
EG Score
5.0(high)
EG Risk
27(Track)
EG Risk 27/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity50% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
8%
KEV
Not listed

Published

August 4, 2026

Last Modified

August 4, 2026

Advisory Details (3)

Auto-updated Aug 4, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic
https://www.cve.org/CVERecord?id=CVE-2026-66300
github_commit

commit b8061add427c (IHTSDO/snowstorm)

Fix landed in IHTSDO/snowstorm commit b8061add427c — awaiting tagged release

https://github.com/IHTSDO/snowstorm/commit/b8061add427c930b3030549e77aa23ec5957ceb6
github_commit

commit 575b55569581 (IHTSDO/snowstorm)

Fix landed in IHTSDO/snowstorm commit 575b55569581 — awaiting tagged release

https://github.com/IHTSDO/snowstorm/commit/575b555695811110dafe2fcea7dd2fd7e4bcee39

Vendor Advisories for CVE-2026-66300(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 18× in last 7d / 47× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 15:25 UTCEG score recompute
  3. 2026-08-20 15:25 UTCGHSA enrichment
  4. 2026-08-19 17:04 UTCEPSS rescore
  5. 2026-08-19 14:07 UTCEG score recompute
  6. 2026-08-19 14:07 UTCGHSA enrichment
  7. 2026-08-18 13:48 UTCEPSS rescore
  8. 2026-08-18 12:51 UTCEG score recompute
  9. 2026-08-18 12:51 UTCGHSA enrichment
  10. 2026-08-17 13:47 UTCEPSS rescore
  11. 2026-08-17 11:35 UTCEG score recompute
  12. 2026-08-17 11:35 UTCGHSA enrichment
  13. 2026-08-16 14:56 UTCEPSS rescore
  14. 2026-08-16 10:20 UTCEG score recompute
  15. 2026-08-16 10:20 UTCGHSA enrichment
  16. 2026-08-15 09:05 UTCEG score recompute
  17. 2026-08-15 09:05 UTCGHSA enrichment
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 07:49 UTCEG score recompute
  20. 2026-08-14 07:49 UTCGHSA enrichment
  21. 2026-08-13 22:00 UTCEPSS rescore
  22. 2026-08-13 06:34 UTCEG score recompute
  23. 2026-08-13 06:34 UTCGHSA enrichment
  24. 2026-08-12 13:51 UTCEPSS rescore
  25. 2026-08-12 05:18 UTCEG score recompute
Show 22 more
  1. 2026-08-12 05:18 UTCGHSA enrichment
  2. 2026-08-11 04:03 UTCEG score recompute
  3. 2026-08-11 04:03 UTCGHSA enrichment
  4. 2026-08-11 00:00 UTCEPSS rescore
  5. 2026-08-10 02:48 UTCEG score recompute
  6. 2026-08-10 02:48 UTCGHSA enrichment
  7. 2026-08-09 13:47 UTCEPSS rescore
  8. 2026-08-09 01:33 UTCEG score recompute
  9. 2026-08-09 01:33 UTCGHSA enrichment
  10. 2026-08-08 16:37 UTCEPSS rescore
  11. 2026-08-08 00:18 UTCEG score recompute
  12. 2026-08-08 00:18 UTCGHSA enrichment
  13. 2026-08-06 23:02 UTCEG score recompute
  14. 2026-08-06 23:02 UTCGHSA enrichment
  15. 2026-08-06 13:47 UTCEPSS rescore
  16. 2026-08-05 21:47 UTCEG score recompute
  17. 2026-08-05 21:47 UTCGHSA enrichment
  18. 2026-08-05 19:17 UTCEPSS rescore
  19. 2026-08-05 19:17 UTCEPSS rescore
  20. 2026-08-04 19:25 UTCEG score recompute
  21. 2026-08-04 18:56 UTCEG score recompute
  22. 2026-08-04 18:55 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66300?
CVE-2026-66300 is a medium vulnerability published on August 4, 2026. 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.
When was CVE-2026-66300 disclosed?
CVE-2026-66300 was first published in the National Vulnerability Database on August 4, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66300 actively exploited?
CVE-2026-66300 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 92.0% of all scored CVEs.
What is the CVSS score of CVE-2026-66300?
CVE-2026-66300 has a CVSS v3 base score of 5.0 (NVD).
How do I remediate CVE-2026-66300?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66300, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66300

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