What’s Vulnerable › Vulnerabilities

CVE-2021-32559

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-06 · updated 2026-06-17
• Weakness: CWE-190

Description

An integer overflow exists in pywin32 prior to version b301 when adding an access control entry (ACE) to an access control list (ACL) that would cause the size to be greater than 65535 bytes. An attacker who successfully exploited this vulnerability could crash the vulnerable process.

Affected products

• Mhammond Pywin32: before 301 — fixed in 301

How to fix

Upgrade to a fixed version: Mhammond Pywin32 301. Check the vendor advisory for mitigations.

References

• https://github.com/fireeye/Vulnerability-Disclosures/blob/master/FEYE-2021-0017/FEYE-2021-0017.md
• https://github.com/mhammond/pywin32/issues/1700
• https://github.com/mhammond/pywin32/pull/1701
• https://github.com/mhammond/pywin32/releases
• https://github.com/fireeye/Vulnerability-Disclosures/blob/master/FEYE-2021-0017/FEYE-2021-0017.md
• https://github.com/mhammond/pywin32/issues/1700
• https://github.com/mhammond/pywin32/pull/1701
• https://github.com/mhammond/pywin32/releases

Get alerted when CVE-2021-32559 or the next vulnerability affects your stack