CVE-2026-17084 (GCVE-0-2026-17084)

Vulnerability from cvelistv5 – Published: 2026-08-18 13:57 – Updated: 2026-08-18 14:05
VLAI
Title
stringprep.map_table_b2() deviates from RFC 3454 Table B.2
Summary
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.
Assigner
Impacted products
Vendor Product Version CPE status
Python Software Foundation CPython Affected: 0 , < 3.16.0 (python)
guessed Create a notification for this product.
Show details on NVD website

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          "value": "Bitshift (https://github.com/TheShiftedBit)"
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          "type": "coordinator",
          "value": "Seth Larson (https://github.com/sethmlarson)"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Stan Ulbrych (https://github.com/StanFromIreland)"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "Marc-Andre Lemburg (https://github.com/malemburg)"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "Petr Viktorin (https://github.com/encukou)"
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        }
      ],
      "metrics": [
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
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            "attackVector": "NETWORK",
            "baseScore": 6,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
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            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "version": "4.0",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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      "providerMetadata": {
        "dateUpdated": "2026-08-18T14:05:20.667Z",
        "orgId": "28c92f92-d60d-412d-b760-e73465c3df22",
        "shortName": "PSF"
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          "url": "https://github.com/python/cpython/pull/155293"
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          "url": "https://github.com/python/cpython/issues/155292"
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          "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/EUHHTC6EV7HCLSUHP25C5VHSV4V2MUZN/"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "stringprep.map_table_b2() deviates from RFC 3454 Table B.2",
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  "cveMetadata": {
    "assignerOrgId": "28c92f92-d60d-412d-b760-e73465c3df22",
    "assignerShortName": "PSF",
    "cveId": "CVE-2026-17084",
    "datePublished": "2026-08-18T13:57:31.876Z",
    "dateReserved": "2026-07-24T14:36:15.943Z",
    "dateUpdated": "2026-08-18T14:05:20.667Z",
    "state": "PUBLISHED"
  },
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  "vulnerability-lookup:meta": {
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  }
}



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