CVE-2021-32559

6.5 MEDIUM 2% exploit odds Fix listed

What it is

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.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. High risk of service disruption.
Exploit odds: 1.7% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-07-06 12:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:53 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.7% in the next 30 days (EPSS).
Severity: 6.5 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-07-06 12:15 UTC
Last modified: 2026-06-17 03:53 UTC
Exploit probability: 1.7% · EPSS, next 30 days
Weakness: CWE-190 · Integer overflow
Record status: Analyzed

Affected

Mhammond pywin32 < 301

Attack profile CVSS 3.1 · 6.5

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-32559.md and follow it. Check whether this project is affected by CVE-2021-32559. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record