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.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 6.0NVD modified 2026-10-22 22:10
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 12
- 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
- https://github.com/python/cpython/commit/d397a4979cfc80a8cd6c73838aa10e9c8cf5ef72
- https://github.com/python/cpython/issues/155292
- https://github.com/python/cpython/pull/155293
- https://mail.python.org/archives/list/[email protected]/thread/EUHHTC6EV7HCLSUHP25C5VHSV4V2MUZN/
- http://www.openwall.com/lists/oss-security/2026/08/18/2