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.
History

Thu, 10 Sep 2026 01:00:00 +0000


Wed, 09 Sep 2026 01:00:00 +0000


Sat, 05 Sep 2026 01:00:00 +0000


Wed, 19 Aug 2026 00:30:00 +0000


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

Type Values Removed Values Added
Weaknesses CWE-20

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

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Metrics ssvc

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


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References

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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

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Weaknesses CWE-20

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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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: PSF

Published: 2026-08-18T13:57:31.876Z

Updated: 2026-09-10T00:35:47.485Z

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: 2026-09-10T01:16:35.477

Link: CVE-2026-17084

cve-icon Redhat

No data.