Vulnerability-Lookup

GHSA-W246-X8QV-R8F5

Vulnerability from github – Published: 2026-08-18 15:31 – Updated: 2026-08-18 18:31

Details

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.

Severity

6.0 (Medium)


                  
                    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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-17084"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-436"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-18T14:16:56Z",
    "severity": "MODERATE"
  },
  "details": "The \"stringprep\" module didn\u0027t process characters from RFC 3454 tables \nB.2 or B.3 correctly: the latest Unicode codepoint attributes were used \ninstead of the specified Unicode 3.2.0. This behavior would cause \nmismatches when processing domain names using IDNA 2003 (the \"idna\" \ncodec) and the in_table_b2() function of the \"stringprep\" module. This \nonly affects domain names containing characters that were not previously\n registered or had their Unicode attributes such as case-folding \nbehavior updated since Unicode 3.2.0.",
  "id": "GHSA-w246-x8qv-r8f5",
  "modified": "2026-08-18T18:31:53Z",
  "published": "2026-08-18T15:31:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-17084"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/155292"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/155293"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/7e109d084d55e7eb25837a5f3b47ef9beee547bc"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/EUHHTC6EV7HCLSUHP25C5VHSV4V2MUZN"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/18/2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2026-08-18 13:57 – Updated: 2026-08-19 00:17

Title

stringprep.map_table_b2() deviates from RFC 3454 Table B.2

Summary

Severity

6 (Medium)


                        
                          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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-18 16:03 UTC

CWE

CWE-436 - Interpretation Conflict

Assigner

PSF mitre root

References

6 references

URL	Tags
https://github.com/python/cpython/pull/155293	patch
https://github.com/python/cpython/issues/155292	issue-tracking
https://mail.python.org/archives/list/security-an…	vendor-advisory
https://github.com/python/cpython/commit/7e109d08…	patch
https://github.com/python/cpython/commit/5181304b…	patch
http://www.openwall.com/lists/oss-security/2026/08/18/2

Impacted products

1 product

Vendor	Product	Version
Python Software Foundation	CPython	Affected: 0 , < 3.15.0 (python)

Credits

Bitshift (https://github.com/TheShiftedBit) Seth Larson (https://github.com/sethmlarson) Stan Ulbrych (https://github.com/StanFromIreland) Marc-Andre Lemburg (https://github.com/malemburg) Petr Viktorin (https://github.com/encukou)

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{
  "containers": {
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                  },
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                "timestamp": "2026-08-18T16:03:21.438212Z",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-W246-X8QV-R8F5

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

Tags

Sightings

Nomenclature