Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-06-05 12:56

Modified

2026-06-05 13:22

Summary

Potential DoS via quadratic complexity in unicodedata.normalize()

Details

unicodedata.normalize() can take excessive CPU time when processing specially crafted Unicode input containing long runs of combining characters with alternating Canonical Combining Class values. This affects all normalization forms.

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "libpython",
        "purl": "pkg:bitnami/libpython"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-3276"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "unicodedata.normalize() can take excessive CPU time when processing\nspecially crafted Unicode input containing long runs of combining characters\nwith alternating Canonical Combining Class values.\nThis affects all normalization forms.",
  "id": "BIT-libpython-2026-3276",
  "modified": "2026-06-05T13:22:57.787Z",
  "published": "2026-06-05T12:56:59.092Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/06/03/15"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/991224b1e8311c85f198f6dd8208bf8cff7fc26f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/ba785b88add96acbf403d65cb157fb2743a33a32"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/c5512bd7c1dc28055660565275012766941d3066"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/149079"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/149080"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/PP5HB4K7727OBBM76KA2ILID76K3OZGZ/"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-3276"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Potential DoS via quadratic complexity in unicodedata.normalize()"
}

CVE-2026-3276 (GCVE-0-2026-3276)

Vulnerability from cvelistv5 – Published: 2026-06-03 14:29 – Updated: 2026-06-04 17:03

Title

Potential DoS via quadratic complexity in unicodedata.normalize()

Summary

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-407

Assigner

PSF

References

8 references

URL	Tags
https://mail.python.org/archives/list/security-an…	vendor-advisory
https://github.com/python/cpython/pull/149080	patch
https://github.com/python/cpython/issues/149079	issue-tracking
https://github.com/python/cpython/commit/6b505d1f…	patch
https://github.com/python/cpython/commit/991224b1…	patch
https://github.com/python/cpython/commit/ba785b88…	patch
https://github.com/python/cpython/commit/c5512bd7…	patch
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version
Python Software Foundation	CPython	Affected: 0 , < 3.15.0b2 (python)

Credits

Seokchan Yoon (https://github.com/ch4n3-yoon) Tim Peters (https://github.com/tim-one) Bénédikt Tran (https://github.com/picnixz) Serhiy Storchaka (https://github.com/serhiy-storchaka) Stan Ulbrych (https://github.com/StanFromIreland) Seth Larson (https://github.com/sethmlarson) Petr Viktorin (https://github.com/encukou)

Show details on NVD website

JSON

To clipboard

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        "metrics": [
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                  },
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                    "Technical Impact": "partial"
                  }
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                "role": "CISA Coordinator",
                "timestamp": "2026-06-03T17:27:09.393265Z",
                "version": "2.0.3"
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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          "product": "CPython",
          "repo": "https://github.com/python/cpython",
          "vendor": "Python Software Foundation",
          "versions": [
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      "credits": [
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          "type": "reporter",
          "value": "Seokchan Yoon (https://github.com/ch4n3-yoon)"
        },
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          "lang": "en",
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          "type": "remediation reviewer",
          "value": "B\u00e9n\u00e9dikt Tran (https://github.com/picnixz)"
        },
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          "lang": "en",
          "type": "remediation reviewer",
          "value": "Serhiy Storchaka (https://github.com/serhiy-storchaka)"
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          ],
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      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
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            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
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        },
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          "tags": [
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          "url": "https://github.com/python/cpython/pull/149080"
        },
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          "tags": [
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          "url": "https://github.com/python/cpython/issues/149079"
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    "datePublished": "2026-06-03T14:29:39.727Z",
    "dateReserved": "2026-02-26T15:19:46.862Z",
    "dateUpdated": "2026-06-04T17:03:12.301Z",
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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.

Action not permitted

Vulnerability from bitnami_vulndb

CVE-2026-3276 (GCVE-0-2026-3276)

Tags

Sightings

Nomenclature