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CVE-2021-32559

22
FAUCET Score

CVE-2021-32559 describes an integer overflow vulnerability in pywin32 versions prior to b301, specifically when adding an Access Control Entry (ACE) to an Access Control List (ACL) that exceeds 65535 bytes. This flaw allows an authenticated attacker to crash the vulnerable process, resulting in a denial of service. With a CVSS score of 6.5 (Medium) and no known public exploits or active exploitation, the immediate risk appears low. Community discussion and media coverage are also minimal, indicating limited external attention.

Impacted Technologies

VendorProductVersion(s)CPE
< 301CPE matchmatch criteria
cpe:2.3:a:mhammond:pywin32:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.73%
Probability of exploitation in next 30 days
EPSS Percentile
75.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0173 is in the 88th percentile among its peer group of 21,974 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: pywin32Fixed in: 301

Vendor Advisories (1)

pipGHSA-hwfp-hg2m-9vr2high

Integer overflow in pywin32

Aug 9, 2021

References

github.com / fireeye/Vulnerability-Disclosures/blob/master/FEYE-2021-0017/FEYE-2021-0017.md
Third Party Advisory
github.com / mhammond/pywin32/issues/1700
PatchThird Party Advisory
github.com / mhammond/pywin32/pull/1701
Third Party Advisory
github.com / mhammond/pywin32/releases
Release NotesThird Party Advisory