CVE-2026-18116

MEDIUMNVD 6.16.1—
EchelonGraph scoreHIGH confidence

Score 6.1 from GitHub Security Advisory (severity: HIGH) published 2026-09-15. NVD baseline CVSS 6.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.1Exploit: None knownExposed services: Not assessed

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

Concrete CMS 8.3.0 to 9.5.2 stored calendar event names without sanitization and rendered them without HTML escaping in the workflow approval and deletion notifications shown in the dashboard "Waiting For Me" block. A registered user permitted to add events to a calendar governed by an approval workflow could submit an event whose name contained a script payload, which then executed in an administrator's browser when the pending request was displayed and could be used to create a new administrator account. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks v01demort for reporting.

CVSS v3
6.1
EG Score
6.1MEDIUMhigh confidence
EG Risk
28
EG Risk 28/100CISA SSVC

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
Severity61% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.2%
EPSS %ILE
3rd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 14, 2026

Last Modified

September 21, 2026

References (1)

Vendor Advisories for CVE-2026-18116(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 / 64× 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. 2026-10-04 23:21 UTCEPSS rescore
  2. 2026-10-04 11:29 UTCEG score recompute
  3. 2026-10-04 11:29 UTCGHSA enrichment
  4. 2026-10-03 14:25 UTCEPSS rescore
  5. 2026-10-03 10:04 UTCEG score recompute
  6. 2026-10-03 10:04 UTCGHSA enrichment
  7. 2026-10-02 08:32 UTCEG score recompute
  8. 2026-10-02 08:32 UTCGHSA enrichment
  9. 2026-10-01 19:49 UTCEPSS rescore
  10. 2026-10-01 07:10 UTCEG score recompute
  11. 2026-10-01 07:10 UTCGHSA enrichment
  12. 2026-09-30 15:02 UTCEPSS rescore
  13. 2026-09-30 05:48 UTCEG score recompute
  14. 2026-09-30 05:48 UTCGHSA enrichment
  15. 2026-09-29 15:20 UTCEPSS rescore
  16. 2026-09-29 04:21 UTCEG score recompute
  17. 2026-09-29 04:21 UTCGHSA enrichment
  18. 2026-09-28 13:51 UTCEPSS rescore
  19. 2026-09-28 02:58 UTCEG score recompute
  20. 2026-09-28 02:58 UTCGHSA enrichment
  21. 2026-09-27 13:47 UTCEPSS rescore
  22. 2026-09-27 01:33 UTCEG score recompute
  23. 2026-09-27 01:32 UTCGHSA enrichment
  24. 2026-09-26 15:58 UTCEPSS rescore
  25. 2026-09-25 23:51 UTCGHSA enrichment
Show 39 more
  1. 2026-09-24 22:02 UTCEG score recompute
  2. 2026-09-24 22:02 UTCGHSA enrichment
  3. 2026-09-23 20:40 UTCEG score recompute
  4. 2026-09-23 20:40 UTCGHSA enrichment
  5. 2026-09-22 19:18 UTCEG score recompute
  6. 2026-09-22 19:18 UTCGHSA enrichment
  7. 2026-09-21 17:55 UTCEG score recompute▼ 1.20
  8. 2026-09-21 17:55 UTCGHSA enrichment
  9. 2026-09-21 17:55 UTCNVD updateCVSS v3 → 6.1 · severity → MEDIUM
  10. 2026-09-21 09:43 UTCGHSA enrichment
  11. 2026-09-20 22:10 UTCEG score recompute
  12. 2026-09-20 22:10 UTCGHSA enrichment
  13. 2026-09-20 10:35 UTCGHSA enrichment
  14. 2026-09-19 22:59 UTCEG score recompute
  15. 2026-09-19 22:59 UTCGHSA enrichment
  16. 2026-09-19 11:25 UTCGHSA enrichment
  17. 2026-09-18 23:50 UTCEG score recompute
  18. 2026-09-18 23:50 UTCGHSA enrichment
  19. 2026-09-18 19:27 UTCEPSS rescore
  20. 2026-09-18 12:17 UTCGHSA enrichment
  21. 2026-09-18 00:43 UTCEG score recompute
  22. 2026-09-18 00:43 UTCGHSA enrichment
  23. 2026-09-17 13:09 UTCGHSA enrichment
  24. 2026-09-17 01:35 UTCEG score recompute
  25. 2026-09-17 01:35 UTCGHSA enrichment
  26. 2026-09-16 14:07 UTCEPSS rescore
  27. 2026-09-16 14:01 UTCEG score recompute
  28. 2026-09-16 14:01 UTCGHSA enrichment
  29. 2026-09-16 05:14 UTCEPSS rescore
  30. 2026-09-16 02:26 UTCGHSA enrichment
  31. 2026-09-15 14:53 UTCGHSA enrichment
  32. 2026-09-15 14:34 UTCEG score recompute
  33. 2026-09-15 14:34 UTCGHSA enrichment
  34. 2026-09-15 13:43 UTCEG score recompute
  35. 2026-09-15 13:43 UTCGHSA enrichment
  36. 2026-09-15 10:56 UTCGHSA enrichment
  37. 2026-09-14 23:22 UTCEG score recompute
  38. 2026-09-14 22:24 UTCEG score recompute
  39. 2026-09-14 22:24 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-18116?
CVE-2026-18116 is a medium vulnerability published on September 14, 2026. Concrete CMS 8.3.0 to 9.5.2 stored calendar event names without sanitization and rendered them without HTML escaping in the workflow approval and deletion notifications shown in the dashboard "Waiting For Me" block. A registered user permitted to add events to a calendar governed by an approval…
When was CVE-2026-18116 disclosed?
CVE-2026-18116 was first published on September 14, 2026, with the most recent update on September 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18116 actively exploited?
CVE-2026-18116 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (3rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-18116?
CVE-2026-18116 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-18116?
No fix for CVE-2026-18116 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-18116 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-18116

Explore →

Is Your Infrastructure Affected by CVE-2026-18116?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs