CVE-2021-32559: 
Python vulnerability analysis and mitigation

An integer overflow vulnerability was discovered in pywin32 prior to version b301, identified as CVE-2021-32559. The vulnerability occurs when adding an access control entry (ACE) to an access control list (ACL) that would cause the size to be greater than 65535 bytes (FireEye Disclosure).

The vulnerability stems from an integer overflow that causes a reduced sized memory allocation, which leads to a heap overflow when an access control entry would cause the access control list to exceed the 65535-byte maximum size. This was reproducible by adding approximately 1800 ACEs to an ACL, though the exact count needed varies based on the SID length in the ACE entry and the current ACL size (GitHub Issue).

The vulnerability has been assessed as having a low impact, primarily resulting in a denial of service condition. If successfully exploited, an attacker could cause the vulnerable process to crash (FireEye Disclosure).

The vulnerability was fixed in pywin32 version b301, released on May 28, 2021. Users are advised to upgrade to this version or later to address the vulnerability (GitHub Release).