Cyber Resilience

CVE-2026-8350

High

Published: 21 May 2026

Published
21 May 2026
Modified
26 May 2026
KEV Added
—
Patch
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CVSS Score v4 7.5 CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/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
EPSS Score 0.0030 21.8th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-8350 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Concretecms Concrete Cms. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 21.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability details

Concrete CMS 9.5.0 and below is vulnerable to missing authorization in the bulk_user_assignment.php which can lead to privilege escalation to Administrative Group. Any authenticated user with access to the bulk user assignment dashboard page can add any user email to…

more

any group and can remove legitimate admins. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Vincent55 for reporting.

CWE(s)
CWE-863

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1098.007 Additional Local or Domain Groups Persistence
An adversary may add additional local or domain groups to an adversary-controlled account to maintain persistent access to a system or domain.
attack.mitre.org →
Why these techniques?

Missing authorization (CWE-863) in Concrete CMS bulk user assignment directly enables privilege escalation (T1068) via unauthorized group membership changes (T1098.007).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Affected Assets

concretecms
concrete cms
≤ 9.5.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-1 Policy and Procedures
addresses: CWE-863

Periodic review and update of procedures reduces incorrect authorization implementations over time.

AC-13 Supervision and Review — Access Control
addresses: CWE-863

Supervision identifies cases where authorization logic incorrectly permits unauthorized actions.

AC-16 Security and Privacy Attributes
addresses: CWE-863

Defining permitted attribute values and auditing modifications reduces the chance of incorrect authorization outcomes due to tampered or missing labels.

AC-17 Remote Access
addresses: CWE-863

The authorization process and usage restrictions help prevent incorrect authorization for remote access types.

AC-18 Wireless Access
addresses: CWE-863

Establishing configuration and connection requirements helps ensure correct rather than incorrect authorization for wireless access.

AC-19 Access Control for Mobile Devices
addresses: CWE-863

Establishing connection authorization processes for mobile devices helps ensure authorization decisions are correctly implemented rather than incorrect.

AC-2 Account Management
addresses: CWE-863

Monitoring account use, notifying on changes, and reviewing accounts for compliance corrects incorrect authorization assignments.

AC-20 Use of External Systems
addresses: CWE-863

Ensures authorization decisions for external system use are correctly implemented and enforced.

References