CVE-2021-31812: 
Java vulnerability analysis and mitigation

CVE-2021-31812 affects Apache PDFBox versions 2.0.23 and prior 2.0.x versions. The vulnerability was discovered and disclosed in June 2021, where a carefully crafted PDF file can trigger an infinite loop while loading the file (OSS Security, Apache Advisory).

The vulnerability is classified as an infinite loop vulnerability (CWE-835: Loop with Unreachable Exit Condition). It has a CVSS v3.1 base score of 5.5 MEDIUM (Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H), indicating local attack vector with low attack complexity, no privileges required, and user interaction required (NVD).

If successfully exploited, the vulnerability can cause a denial of service condition through an infinite loop when loading a specially crafted PDF file, affecting the availability of the system (NVD).

The vulnerability requires a user to attempt to load a maliciously crafted PDF file. No known exploits in the wild have been reported at the time of disclosure (OSS Security).

The vulnerability was fixed in Apache PDFBox version 2.0.24. All users are recommended to upgrade to this version or later. The fix was also backported to various distributions including Fedora (Fedora Update).