The vulnerability lies in the local_iomad_pluginfile function within iomad's PDF Certificate Handler, allowing an attacker to bypass authorization checks and access files intended to be restricted. This can result in the unauthorized retrieval or manipulation of PDF certificates, compromising data confidentiality and potentially enabling further attacks such as credential disclosure or fraud. The weakness is formally classified as improper authorization and unauthorized credential use.

Affected releases include iomad up to version 4.5.15, 5.0.11, 5.1.8, and 5.2.4. The flaw is present in the lib.php library of the PDF Certificate Handler component. Systems running any of these versions of iomad are therefore vulnerable and should be evaluated for potential exposure.

The CVSS score of 5.3 reflects moderate severity; exploitation does not require local access and can be performed remotely. The ESPS score is not available, and the vulnerability is not listed in CISA KEV, indicating limited public exploitation data. Attackers can trigger the bypass by sending crafted requests to the PDF Certificate Handler endpoint, gaining access to files without proper authorization. The presence of CWE-285 and CWE-639 underscores the nature of the authorization flaw and the potential for credential misuse.