CVE-2026-17084
mediumpriority · track · 0EPSS 0.007 · 54 %ileDEUSEPSS · scored 2026-10-22
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 2.3–6
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (23)
Products and version ranges known to be affected.
advisories (5)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-2924CPython: Mehrere SchwachstellenDeutsch2026-08-18csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in CPython ausnutzen, um Informationen offenzulegen und um nicht näher spezifizierte Auswirkungen zu erzielen.
- BIT-libpython-2026-17084stringprep.map_table_b2() deviates from RFC 3454 Table B.22026-09-11vendor · osvUS
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.
- BIT-python-2026-17084stringprep.map_table_b2() deviates from RFC 3454 Table B.22026-09-11vendor · osvUS
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.
- BIT-python-min-2026-17084stringprep.map_table_b2() deviates from RFC 3454 Table B.22026-09-11vendor · osvUS
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.
- PSF-2026-372026-08-18vendor · osvUS
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.
also known as (4)
Other names and identifiers for this entity.
sources
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references (12) nvd
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2026/08/18/2
- https://github.com/python/cpython/commit/1e54caa096678a38afcabecabb1ff72400dd6bae
- https://github.com/python/cpython/commit/5181304bcec9cfc3c15311741c9154cdff2e3fd7
- https://github.com/python/cpython/commit/69f92ebaec681e9149dfd70fd02d4ed52d2a6296
- https://github.com/python/cpython/commit/7e109d084d55e7eb25837a5f3b47ef9beee547bc
- https://github.com/python/cpython/commit/c016c2535b74227fddf2cf7334dbfead6c930214
- https://github.com/python/cpython/commit/c28b121a4f0b975937c8b5a1b4934bb361d84296
- https://github.com/python/cpython/commit/c42790b34f634051750e5da340d17c7da19e4784
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