A heap buffer overflow is triggered when libXfont2 parses PCF font files in its ComputeScaledProperties function. The bug stems from a missing size check on the property buffer, allowing an attacker to overwrite heap memory and gain arbitrary code execution in the X server process. This flaw is classified as a buffer overflow, identified as CWE-122, and could compromise confidentiality, integrity, and availability of the affected system.

The vulnerability affects the X.Org libXfont2 component in all releases before version 2.0.8. Systems that run an older library and allow authenticated X clients to load PCF fonts are susceptible to exploitation. All such affected installations are at risk if they are exposed to any client capable of crafting a malicious PCF file,

The CVSS score of 8.5 reflects high severity, while the EPSS score of less than 1% indicates a very low probability of exploitation at this time; the flaw is not listed in the CISA KEV catalog. Exploitation requires an authenticated X client that can supply a crafted PCF file, which then triggers the overflow and runs code at the privilege level of the X server. The attack vector is therefore an authenticated local or network client that can interact with the server.