VulnerabilityPublished 29 Apr 2026Updated 8 May 2026

CVE-2026-41662: Role Membership Removal · Admidio Missing Minimum Administrator Check

Affects admidio/admidioSource GCVE Database

Authoritative record:CVE-2026-41662· Medium 5.2

Not known to be exploited · CVSS 5.2 Medium : upgrade to 5.0.9 when convenient.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score

5.2Medium

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 5.0.9

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 7 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade admidio/admidio to 5.0.9.

Affected software

Product	Affected	Fixed in
Packagistadmidio/admidio	Affected <5.0.9	Fixed in 5.0.9

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

## Summary `Role::stopMembership()` does not verify whether removing a user from the administrator role leaves zero administrators. The deprecated `Membership::stopMembership()` contains this safety check, but the current code path bypasses it. Any administrator can remove the last remaining other administrator, locking the entire system out of administrative access. The exploit does not require concurrent requests; sequential removals produce the same result. ## Details `Role::stopMembership()` in `src/Roles/Entity/Role.php` stops a user's membership in a role without verifying whether the action leaves the administrator role with zero members: ```php // src/Roles/Entity/Role.php - Role::stopMembership() public function stopMembership(int $userId): bool { // No check for minimum administrator count // Directly updates membership end date } ``` The deprecated `Membership::stopMembership()` contains this safety check and raises `SYS_MUST_HAVE_ADMINISTRATOR` when the removal would leave no admins, but current code paths no longer call this method. `Role::setMembership()` includes a guard that prevents a user from removing their own administrator membership: ```php if ($userId === $gCurrentUserId) { // Prevents self-removal from admin role } ``` This guard does not prevent an administrator from removing the last other administrator. Consider a system with exactly two administrators (Admin A and Admin B): 1. Admin A removes Admin B from the administrator role. The self-removal check passes (Admin A is not removing themselves). No minimum-count check runs. Admin B loses admin access. 2. Admin A is now the sole administrator. Admin A cannot remove themselves (self-removal guard), but the system is one compromised account away from total lockout. 3. If Admin A and Admin B each send a removal request for the other (sequentially or concurrently), both succeed. The system has zero administrators. The core bug is the missing minimum-administrator check in `Role::stopMembership()`, not timing. Sequential requests reproduce the issue just as concurrent ones do. ## Proof of Concept Requirements: two active administrator accounts (Admin A and Admin B) with valid sessions. ```python import requests BASE = "https://admidio.example.com" session_a = requests.Session() session_b = requests.Session() # Authenticate both sessions (login step omitted for brevity) # Step 1: Admin A removes Admin B (sequential, no race needed) resp1 = session_a.post(f"{BASE}/modules/profile/profile_function.php", data={ "mode": "stop_membership", "user_uuid": ADMIN_B_UUID, "role_uuid": ADMIN_ROLE_UUID }) print(f"Admin A removes Admin B: {resp1.status_code}") # 200 # Step 2: Admin B removes Admin A (Admin B's session is still valid) resp2 = session_b.post(f"{BASE}/modules/profile/profile_function.php", data={ "mode": "stop_membership", "user_uuid": ADMIN_A_UUID, "role_uuid": ADMIN_ROLE_UUID }) print(f"Admin B removes Admin A: {resp2.status_code}") # 200 # The system now has 0 administrators. ``` After both requests complete, no users remain in the administrator role. The administrative interface becomes inaccessible. Recovery requires direct database manipulation to reassign the administrator role. ## Impact Two colluding or compromised administrator accounts lock out all administrative access to the Admidio installation. Recovery demands direct database access, which may not be available on shared hosting environments. The attack does not require precise timing because `Role::stopMembership()` performs no minimum-admin-count check at all. ## Recommended Fix Add a minimum-administrator-count check to `Role::stopMembership()`. Before stopping a membership in the administrator role, query the current count of active members. If stopping this membership would leave zero administrators, reject the request with `SYS_MUST_HAVE_ADMINISTRATOR`. This mirrors the check already present in the deprecated `Membership::stopMembership()` method. --- *Found by [aisafe.io](https://aisafe.io)*

CWE-754Improper Check for Unusual or Exceptional Conditions (opens in a new tab)
Class weaknessLikelihood of exploit: MediumOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation
Check the results of all functions that return a value and verify that the value is expected.
Implementation
If using exception handling, catch and throw specific exceptions instead of overly-general exceptions (CWE-396, CWE-397). Catch and handle exceptions as locally as possible so that exceptions do not propagate too far up the call stack (CWE-705). Avoid unchecked or uncaught exceptions where feasible (CWE-248).
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-754

Technical details

References

Community reviews

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