The "stringprep" module didn't process characters from RFC 3454 tables
B.2 or B.3 correctly: the latest Unicode codepoint attributes were used
instead of the specified Unicode 3.2.0. This behavior would cause
mismatches when processing domain names using IDNA 2003 (the "idna"
codec) and the in_table_b2() function of the "stringprep" module. This
only affects domain names containing characters that were not previously
registered or had their Unicode attributes such as case-folding
behavior updated since Unicode 3.2.0.

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History

Tue, 18 Aug 2026 19:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20

Tue, 18 Aug 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 18 Aug 2026 18:15:00 +0000


Tue, 18 Aug 2026 17:30:00 +0000

Type Values Removed Values Added
References

Tue, 18 Aug 2026 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Python
Python cpython
Vendors & Products Python
Python cpython

Tue, 18 Aug 2026 16:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-436

Tue, 18 Aug 2026 16:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20

Tue, 18 Aug 2026 14:30:00 +0000

Type Values Removed Values Added
Title stringprep.map_table_b2() deviates from RFC 3454 Table B.2 — breaks IDNA interoperability stringprep.map_table_b2() deviates from RFC 3454 Table B.2

Tue, 18 Aug 2026 14:00:00 +0000

Type Values Removed Values Added
Description The "stringprep" module didn't process characters from RFC 3454 tables B.2 or B.3 correctly: the latest Unicode codepoint attributes were used instead of the specified Unicode 3.2.0. This behavior would cause mismatches when processing domain names using IDNA 2003 (the "idna" codec) and the in_table_b2() function of the "stringprep" module. This only affects domain names containing characters that were not previously registered or had their Unicode attributes such as case-folding behavior updated since Unicode 3.2.0.
Title stringprep.map_table_b2() deviates from RFC 3454 Table B.2 — breaks IDNA interoperability
References
Metrics cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: PSF

Published:

Updated: 2026-08-18T18:02:43.165Z

Reserved: 2026-07-24T14:36:15.943Z

Link: CVE-2026-17084

cve-icon Vulnrichment

Updated: 2026-08-18T17:08:22.725Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-08-18T14:16:56.290

Modified: 2026-08-18T18:17:26.490

Link: CVE-2026-17084

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T21:00:04Z

Weaknesses