Cyber Resilience

CVE-2026-58054

HighPublic PoC

Published: 28 June 2026

Published
28 June 2026
Modified
29 June 2026
KEV Added
Patch
CVSS Score v4 8.6 CVSS:4.0/AV:N/AC:L/AT:N/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 0.0027 19.0th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-58054 is a high-severity Improper Privilege Management (CWE-269) vulnerability. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 19.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability details

MyBB 1.8.40 does not restrict which usergroup a limited Admin Control Panel user may assign when creating or editing users; the user module offers the Administrators group (gid 4) and its datahandler's verify_usergroup() unconditionally returns true. An admin holding only…

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the delegated user-management permission can assign the Administrators group to an account and escalate to the full Administrator permission set.

CWE(s)

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.
Why these techniques?

Direct privilege escalation via improper usergroup assignment in admin panel, matching T1068.

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

CVEs Like This One

CVE-2026-33821Shared CWE-269
CVE-2025-49758Shared CWE-269
CVE-2025-2858Shared CWE-269
CVE-2026-11295Shared CWE-269
CVE-2024-2297Shared CWE-269
CVE-2025-50062Shared CWE-269
CVE-2025-64487Shared CWE-269
CVE-2026-45716Shared CWE-269
CVE-2025-37186Shared CWE-269
CVE-2025-43199Shared CWE-269

Affected Assets

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.

addresses: CWE-269

Policy addresses roles, responsibilities, and privilege management to prevent improper privilege assignments.

addresses: CWE-269

Access supervision ensures privileges are assigned and managed without improper escalation or retention.

addresses: CWE-269

Assigning group/role memberships and access authorizations (privileges) while reviewing accounts addresses improper privilege management.

addresses: CWE-269

Enforces proper privilege management by requiring all decisions through the verified reference monitor.

addresses: CWE-269

By mandating division of duties across roles, the control enforces proper privilege management and prevents a single entity from controlling an entire sensitive process.

addresses: CWE-269

Implements core proper privilege management by restricting to only required rights.

addresses: CWE-269

Policy requires training on privilege management and least privilege, making it harder to exploit improper privilege management weaknesses.

addresses: CWE-269

Training covers proper privilege management practices, making incorrect privilege assignments less likely.

Hardening callouts derived

Configuration rules from DISA STIG baselines that reduce the attack surface for weaknesses of the type cited by this CVE. Derived transitively via CVE→CWE→STIG over `controls_xwalks` (authoritative rows only).

Windows 10 (1 rule)
  • V-220712 Only accounts responsible for the administration of a system must have Administrator rights on the system. via CWE-269
Windows 11 (1 rule)
  • V-253269 Only accounts responsible for the administration of a system must have Administrator rights on the system. via CWE-269
Windows Server 2016 (1 rule)
  • V-225007 Only administrators responsible for the member server or standalone or nondomain-joined system must have Administrator rights on the system. via CWE-269
Windows Server 2019 (1 rule)
  • V-205746 Windows Server 2019 must only allow Administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. via CWE-269
Windows Server 2022 (1 rule)
  • V-254428 Windows Server 2022 must only allow administrators responsible for the member server or standalone or nondomain-joined system to have Administrator rights on the system. via CWE-269

References