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CVE-2026-81896

HIGH 8.4 ALL-YEARS

Published 2026-09-15 · Last modified 2026-09-22 · ConcreteCMS · NVD: Analyzed

Concrete CMS before 9.5.3 does not apply HTML entity encoding to user-defined Form block question labels when rendering them as column headers in the Dashboard Form Submissions report (concrete/single_pages/dashboard/reports/forms/legacy.php). a rogue editor could store markup or script in a label that then executes in the browser of any administrator who opens the submissions report for the affected form, producing stored cross-site scripting in the Dashboard. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 8.4 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

ELEVATED IMPACT

Severe if exploited (CVSS 8.4), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 14th percentile

○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

8.4CVSS 4.0 · HIGH · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires an admin / high-privilege account
  • ⚠User interaction: Succeeds with passive user activity
  • ✓Complexity: No special conditions — reliably repeatable
  • ✓Requirements: No special attack requirements

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.

Affected

Vendors Concrete Cms Concretecms

Products Concrete Cms

Weakness (CWE)

  • CWE-79: Improper Neutralization of Input During Web Page Generation

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Known Affected Software Configurations

VendorProductVersion range
ConcretecmsConcrete Cms< 9.5.3

All CVSS metrics

  • HIGH 8.4 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
  • HIGH 8.4 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
  • MEDIUM 5.4 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

References

Patches & mitigations

Sources: NVD · CVE.org · EPSS