CVE-2026-17084
stringprep.map_table_b2() deviates from RFC 3454 Table B.2
At a glance
- Severity
- MEDIUM 6.0
- EPSS
- EPSS 0.73 % · percentile 54 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- PSF
- NVD status
- Awaiting Analysis
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.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 6.0 | 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 | PSF |
| CVSS 4.0 | MEDIUM 6.0 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · cna@python.org (Secondary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2026-60889
- GCVE · GCVE-0-2026-17084
CERT-FR advisories
- CERTFR-2026-AVI-1249 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1044 — Multiples vulnérabilités dans Python · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| Python Software Foundation · CPython | affected 0 < 3.10.22 ; affected 3.11.0 < 3.11.17 ; affected 3.12.0 < 3.12.15 ; affected 3.13.0 < 3.13.16 ; affected 3.14.0 < 3.14.8 ; affected 3.15.0a1 < 3.15.0rc2 |
References
- https://github.com/python/cpython/pull/155293
- https://github.com/python/cpython/issues/155292
- https://mail.python.org/archives/list/security-announce@python.org/thread/EUHHTC6EV7HCLSUHP25C5VHSV4V2MUZN/
- https://github.com/python/cpython/commit/7e109d084d55e7eb25837a5f3b47ef9beee547bc
- https://github.com/python/cpython/commit/5181304bcec9cfc3c15311741c9154cdff2e3fd7
- https://github.com/python/cpython/commit/1e54caa096678a38afcabecabb1ff72400dd6bae
- 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/69f92ebaec681e9149dfd70fd02d4ed52d2a6296
- https://github.com/python/cpython/commit/d397a4979cfc80a8cd6c73838aa10e9c8cf5ef72
- http://www.openwall.com/lists/oss-security/2026/08/18/2
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |