Cyber Resilience

CVE-2026-59890

Python Setuptools ≤ 83.0.0

Public PoC
Published
08 July 2026
Modified
13 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
EPSS Score 0.0040 34th percentile
Risk Priority 47 floored blend · peak EPSS

Summary

CVE-2026-59890 is a medium-severity Improper Handling of Unicode Encoding (CWE-176) vulnerability in Python Setuptools. Its CVSS base score is 6.1 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Invisible Unicode (T1027.018); ranked at the 34th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

setuptools is a package that allows users to download, build, install, upgrade, and uninstall Python packages. Prior to 83.0.0, FileList applied MANIFEST.in exclude, global-exclude, recursive-exclude, and prune directives by matching compiled glob patterns against on-disk file names without Unicode normalization,…

more

so on macOS APFS or HFS+ an NFD file name could bypass an NFC exclusion rule and be packed into a source distribution. This issue is fixed in version 83.0.0.

CWE(s)
CWE-176CWE-697

Related Threats

MITRE ATT&CK Enterprise Techniques

T1027.018 Invisible Unicode Stealth
Adversaries may abuse invisible or non-printing Unicode characters to conceal malicious content within files, scripts, or text.
attack.mitre.org →
T1027 Obfuscated Files or Information Stealth
Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1132 Data Encoding Command And Control
Adversaries may encode data to make the content of command and control traffic more difficult to detect.
attack.mitre.org →
T1132.002 Non-Standard Encoding Command And Control
Adversaries may encode data with a non-standard data encoding system to make the content of command and control traffic more difficult to detect.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-47273Same product: Python Setuptools
CVE-2023-33595Same vendor: Python
CVE-2026-54058Same vendor: Python
CVE-2026-59198Same vendor: Python
CVE-2025-12781Same vendor: Python
CVE-2026-59199Same vendor: Python
CVE-2026-59205Same vendor: Python
CVE-2026-59197Same vendor: Python
CVE-2023-6507Same vendor: Python
CVE-2026-31900Same vendor: Python

Affected Assets

python
setuptools
≤ 83.0.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation directly exercises security-relevant comparisons to discover incorrect logic.

SI-10 Information Input Validation good match

Input validation directly requires checking and normalizing encodings so that Unicode is handled consistently before further processing.

AC-25 Reference Monitor partial match

A reference monitor must be small and correct, structurally limiting the chance of flawed comparison logic in authorization decisions.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles require correct implementation of comparison logic used for access and authentication decisions.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper Unicode/input validation to prevent this weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect Unicode-handling flaws before deployment.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and encoding handling that can prevent Unicode mishandling.

A.8.26 Application security requirements partial match
prevents

Application security requirements include proper handling of character encodings and input sanitization.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles require robust input processing to avoid encoding-related vulnerabilities.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address proper Unicode and character-encoding validation.

A.8.5 Secure authentication partial match
degrades

Secure authentication mechanisms rely on correct comparison of credentials or tokens.

References