The vulnerability located in Alinto SOGo 5.12.3 and 5.12.4 allows an attacker to inject arbitrary script code into web pages through manipulation of the "hint" argument. Because the injection point is rendered without proper encoding, an attacker can run scripts in the victim's browser session, leading to possible session hijacking, phishing, or data theft. The weakness is identified as a classic reflected XSS (CWE‑79) combined with unsafe code execution pathways (CWE‑94). The defacement originates from an unspecified internal function that processes the hint parameter.

The affected product is Alinto SOGo versions 5.12.3 and 5.12.4. No other vendor or product versions are listed in the advisory.

The CVSS score is 5.3, indicating moderate severity, while the EPSS score is less than 1% which suggests a relatively low probability of exploitation. The flaw is remote and publicly exploitable, meaning an attacker only needs a user to visit a crafted URL or interact with malicious content. Although the risk appears moderate and the vulnerability is not listed in the CISA KEV catalog, the lack of an official vendor fix necessitates proactive remediation if the software is in use.