CVE-2026-58054
MyBB - Privilege Escalation from Limited ACP User Management to Administrator
Description
Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority. This CVE was assigned on the basis that the permission system allows a limited administrator to grant privileges exceeding their own authorization scope, potentially constituting an insecure default configuration. Following a dispute, the MITRE TL-Root determined the behavior reflects documented and intended product design rather than a security vulnerability.
INFO
Published Date :
June 28, 2026, 2:16 a.m.
Last Modified :
July 24, 2026, 7:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update MyBB to patch the usergroup assignment vulnerability.
- Verify usergroup assignments during user creation/editing.
- Restrict 'Administrators' group assignment privileges.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-58054 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-58054 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Rejected by [email protected]
Jul. 24, 2026
Action Type Old Value New Value -
CVE Modified by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Changed Description 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 the delegated user-management permission can assign the Administrators group to an account and escalate to the full Administrator permission set. Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority. This CVE was assigned on the basis that the permission system allows a limited administrator to grant privileges exceeding their own authorization scope, potentially constituting an insecure default configuration. Following a dispute, the MITRE TL-Root determined the behavior reflects documented and intended product design rather than a security vulnerability. Removed CVSS V4.0 VulnCheck: 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 Removed CVSS V3.1 VulnCheck: AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H Removed CWE VulnCheck: CWE-269 Removed Reference VulnCheck: https://github.com/bikini/exploitarium/tree/main/mybb-limited-acp-to-admin Removed Reference VulnCheck: https://www.vulncheck.com/advisories/mybb-privilege-escalation-from-limited-acp-user-management-to-administrator Removed Affected [{'vendor': 'MyBB', 'product': 'MyBB', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '1.8.40'}], 'defaultStatus': 'affected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 29, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-58054', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-29T13:03:18.669621Z'} -
New CVE Received by [email protected]
Jun. 28, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'MyBB', 'product': 'MyBB', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '1.8.40'}], 'defaultStatus': 'affected'}] Added Description 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 the delegated user-management permission can assign the Administrators group to an account and escalate to the full Administrator permission set. Added CVSS V4.0 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 Added CVSS V3.1 AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-269 Added Reference https://github.com/bikini/exploitarium/tree/main/mybb-limited-acp-to-admin Added Reference https://www.vulncheck.com/advisories/mybb-privilege-escalation-from-limited-acp-user-management-to-administrator