CVE-2026-34390 | MantisBT: Privilege Escalation from Manager to Administrator

Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and prior have a Privilege Escalation vulnerability where insufficient access control checks in ProjectUsersAddCommand (manage_proj_user_add.php) allow users having manage_project_threshold access level (manager by default) to grant project-level administrator access to any user (including themselves) in any Project they have manager rights in. The normal project-user add form restricts the selectable access levels to the actor's own project role or below. However, the backend handler still accepts a forged higher access_level value and writes it. The consequences of the privilege escalation are slight, as having administrator access at Project level is effectively not very different from being manager, and it does not actually give administrator privileges on the whole MantisBT instance. In particular, it does not let the upgraded user delete the Project or grant them any access to global administrative functions such as managing Users, Projects, Plugins, Custom Fields, etc. This issue has been fixed in version 2.28.2.

Published: 2026-05-19 Last update: 2026-05-20 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-34390 is rated Low Risk (32.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.43%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-34390

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.04% 0.43% +0.39%
2 2026-05-20 0.04%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34390

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.1 4.0 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/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 Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:H)
High privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:L)
Limited confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L)
Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
[email protected]

Weakness enumeration for CVE-2026-34390

GitHub Security Advisory for CVE-2026-34390

GHSA-frf7-jhp9-jxm6 · Severity: medium · Ecosystem: composer — MantisBT Vulnerable to Privilege Escalation from Manager to Administrator

Affected software / configurations for CVE-2026-34390

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-34390

cvelogic Threat Intelligence