CVE-2026-114611 in OCO-Server
Summary
by MITRE • 10/23/2026
OCO-Server is a self-hosted endpoint management application for computer inventory, software deployment, and mobile device management. Prior to 1.2.3,the Apple MDM enrollment endpoint `frontend/api-mdm.php` verifies the signed enrollment-request plist with `openssl_pkcs7_verify(..., PKCS7_NOVERIFY, ...)`. `PKCS7_NOVERIFY` disables signer certificate chain and trust validation, so the signature only has to be self-consistent with whatever certificate is embedded in the PKCS#7 blob. A self-signed certificate from an unrelated attacker is accepted. Because the endpoint trusts the `SERIAL` field taken from the unverified payload, anyone who knows a registered device's serial number can sign a forged plist (`SERIAL` = victim device, attacker-chosen `UDID`) with an arbitrary self-signed certificate; POST it unauthenticated to `/api-mdm.php/profile` (Content-Type: `application/pkcs7-signature`); and receive the victim device's freshly minted MDM identity: a certificate with `CN=<serial>` issued by the server's internal MDM device CA, bundled with its private key in a PKCS#12 payload inside the returned `.mobileconfig` enrollment profile. Additionally, the victim's `mobile_device` database row is silently overwritten with the attacker-supplied `UDID` (device-record hijack). With the stolen certificate and key, the attacker can impersonate the victim device on all subsequent MDM traffic (`/checkin`, `/mdm`, `/parameters`), which authenticate callers by the certificate CN (the serial number) via `checkSignature()` in the same file. This yields control over the victim device's MDM relationship: reading its management data, replacing its push token, and disrupting or redirecting its enrollment. Version 1.2.3 fixes the issue.
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Analysis
by VulDB Data Team • 10/23/2026
OCO-Server is a self-hosted endpoint management application designed for computer inventory tracking, software deployment, and mobile device management. A critical vulnerability exists in versions prior to 1.2.3 within the Apple MDM enrollment endpoint located at frontend/api-mdm.php. The core technical flaw lies in how this endpoint verifies signed enrollment requests using the openssl_pkcs7_verify function with the PKCS7_NOVERIFY flag enabled. This configuration disables signer certificate chain and trust validation, meaning the signature verification process only checks if the cryptographic signature is self-consistent with whatever certificate is embedded within the PKCS#7 blob. Consequently, a self-signed certificate from an unrelated attacker is accepted as valid without any check against trusted root authorities or internal CA lists.
This lack of strict authentication allows for a severe device-record hijacking attack. An adversary who knows a registered victim device's serial number can forge a plist file by setting the SERIAL field to match that of the victim while assigning an arbitrary UDID chosen by the attacker. By signing this forged payload with their own self-signed certificate and submitting it unauthenticated via POST request to /api-mdm.php/profile with the Content-Type application/pkcs7-signature, the server processes the request as legitimate. The system then issues a fresh MDM identity for the victim device: a certificate where the Common Name matches the victim's serial number, issued by the server's internal MDM device CA. This certificate is bundled with its private key in a PKCS#12 payload contained within the returned .mobileconfig enrollment profile. Simultaneously, the database row for the victim's mobile_device record is silently overwritten to associate it with the attacker-supplied UDID rather than the original hardware identifier.
The operational impact of this vulnerability grants an attacker complete control over the victim device's MDM relationship and identity. With possession of the stolen certificate and private key, the attacker can impersonate the victim device in all subsequent MDM communications, including endpoints such as /checkin, /mdm, and /parameters. These interactions authenticate callers based on the certificate CN, which corresponds to the serial number, verified via checkSignature() within the same file. This capability allows an adversary to read sensitive management data associated with the victim device, replace its push notification token to intercept alerts or commands, and disrupt or redirect future enrollment processes. The attacker effectively seizes administrative control over the managed asset without needing valid credentials for that specific device instance.
This vulnerability is classified under CWE-295 Improper Certificate Validation because the application fails to properly validate certificates against a trusted list of issuers during the PKCS#7 verification process. In terms of attack tactics, this aligns with MITRE ATT&CK technique T1608 Install Root Certificate, as the exploitation involves manipulating certificate trust relationships, and potentially T1539 Steal Web Session Cookie if session tokens are derived from MDM identities, though primarily it represents a failure in authentication logic leading to identity theft. The vulnerability enables unauthorized access to sensitive management infrastructure by bypassing expected cryptographic assurances of origin.
To mitigate this risk, organizations running OCO-Server must upgrade immediately to version 1.2.3 or later, which addresses the improper certificate validation flaw. Until an update is applied, administrators should restrict network access to the frontend/api-mdm.php endpoint using firewall rules or reverse proxy configurations that limit exposure to untrusted networks. Additionally, implementing strict input validation and ensuring that all cryptographic verification functions enforce full chain-of-trust validation rather than relying on self-consistent signatures alone can provide a defensive layer against similar exploitation attempts in other components of the management suite.