CVE-2026-81903

MEDIUMNVD 5.45.4—
EchelonGraph scoreHIGH confidence

Score 5.4 from GitHub Security Advisory (severity: HIGH) published 2026-09-14. NVD baseline CVSS 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

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

Concrete CMS versions 9.0.0 to 9.5.2 stored the Page Container icon value submitted through the dashboard without validating it against the set of known container icons. The unvalidated value was later concatenated into the src attribute of an img tag by a helper that did not encode attribute output, and was rendered raw in the Containers dashboard list and editor views. A user with delegated access to the Page Containers dashboard could store a crafted icon value that broke out of the src attribute and executed script in the authenticated session of another editor or administrator who viewed the list, enabling session token theft and privileged dashboard actions. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.0 with vector CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Andrew Gonzalez for reporting.

CVSS v3
5.4
EG Score
5.4(high)
EG Risk
24(Track)
EG Risk 24/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

September 14, 2026

Last Modified

September 18, 2026

References (1)

Vendor Advisories for CVE-2026-81903(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 20× in last 7d / 38× 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. 2026-09-24 19:15 UTCEG score recompute
  2. 2026-09-24 19:15 UTCGHSA enrichment
  3. 2026-09-24 14:04 UTCEPSS rescore
  4. 2026-09-23 19:22 UTCEG score recompute
  5. 2026-09-23 19:22 UTCGHSA enrichment
  6. 2026-09-23 17:54 UTCEPSS rescore
  7. 2026-09-22 19:01 UTCEG score recompute
  8. 2026-09-22 19:00 UTCGHSA enrichment
  9. 2026-09-22 16:01 UTCEPSS rescore
  10. 2026-09-21 21:09 UTCEPSS rescore
  11. 2026-09-21 19:08 UTCEG score recompute
  12. 2026-09-21 19:08 UTCGHSA enrichment
  13. 2026-09-20 20:16 UTCEPSS rescore
  14. 2026-09-20 19:15 UTCGHSA enrichment
  15. 2026-09-19 19:23 UTCEG score recompute
  16. 2026-09-19 19:23 UTCGHSA enrichment
  17. 2026-09-18 19:30 UTCEG score recompute▼ 1.60
  18. 2026-09-18 19:30 UTCGHSA enrichment
  19. 2026-09-18 19:28 UTCEPSS rescore
  20. 2026-09-18 19:26 UTCNVD updateCVSS v3 → 5.4 · severity → MEDIUM
  21. 2026-09-18 07:39 UTCEG score recompute
  22. 2026-09-18 07:39 UTCGHSA enrichment
  23. 2026-09-17 19:25 UTCGHSA enrichment
  24. 2026-09-17 04:14 UTCGHSA enrichment
  25. 2026-09-16 15:59 UTCEG score recompute
Show 13 more
  1. 2026-09-16 15:59 UTCGHSA enrichment
  2. 2026-09-16 14:08 UTCEPSS rescore
  3. 2026-09-16 05:15 UTCEPSS rescore
  4. 2026-09-16 03:46 UTCGHSA enrichment
  5. 2026-09-15 15:32 UTCEG score recompute
  6. 2026-09-15 15:32 UTCGHSA enrichment
  7. 2026-09-15 15:01 UTCEG score recompute
  8. 2026-09-15 15:01 UTCGHSA enrichment
  9. 2026-09-15 09:46 UTCGHSA enrichment
  10. 2026-09-14 21:33 UTCEG score recompute
  11. 2026-09-14 21:33 UTCGHSA enrichment
  12. 2026-09-14 20:26 UTCEG score recompute
  13. 2026-09-14 20:24 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81903?
CVE-2026-81903 is a medium vulnerability published on September 14, 2026. Concrete CMS versions 9.0.0 to 9.5.2 stored the Page Container icon value submitted through the dashboard without validating it against the set of known container icons. The unvalidated value was later concatenated into the src attribute of an img tag by a helper that did not encode attribute…
When was CVE-2026-81903 disclosed?
CVE-2026-81903 was first published in the National Vulnerability Database on September 14, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81903 actively exploited?
CVE-2026-81903 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 77.5% of all scored CVEs.
What is the CVSS score of CVE-2026-81903?
CVE-2026-81903 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-81903?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81903, 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

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