CVE-2026-17084stringprep.map_table_b2() deviates from RFC 3454 Table B.2
Updated under an hour ago ()
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It affects Python Software Foundation CPython. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 6.0 MEDIUM (v4.0, CNA)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
- Weakness (CWE)
- CWE-436
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- PSF
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 2, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Python Software Foundation CPython python_software_foundation:cpython (from the name) | before 3.10.22; from 3.11.0 before 3.11.17; from 3.12.0 before 3.12.15; from 3.13.0 before 3.13.16; from 3.14.0 before 3.14.8; from 3.15.0a1 before 3.15.0rc2 | CNA record |
References
- https://github.com/python/cpython/pull/155293patch
- https://github.com/python/cpython/issues/155292issue-tracking
- https://mail.python.org/archives/list/security-announce@python.org/thread/EUHHTC6EV7HCLSUHP25C5VHSV4V2MUZN/vendor-advisory
- https://github.com/python/cpython/commit/7e109d084d55e7eb25837a5f3b47ef9beee547bcpatch
- https://github.com/python/cpython/commit/5181304bcec9cfc3c15311741c9154cdff2e3fd7patch
- https://github.com/python/cpython/commit/1e54caa096678a38afcabecabb1ff72400dd6baepatch
- https://github.com/python/cpython/commit/c016c2535b74227fddf2cf7334dbfead6c930214patch
- https://github.com/python/cpython/commit/c28b121a4f0b975937c8b5a1b4934bb361d84296patch
- https://github.com/python/cpython/commit/c42790b34f634051750e5da340d17c7da19e4784patch
- https://github.com/python/cpython/commit/69f92ebaec681e9149dfd70fd02d4ed52d2a6296patch
- https://github.com/python/cpython/commit/d397a4979cfc80a8cd6c73838aa10e9c8cf5ef72patch
- http://www.openwall.com/lists/oss-security/2026/08/18/2
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.