FKIE_CVE-2026-3276

Vulnerability from fkie_nvd - Published: 2026-06-03 16:16 - Updated: 2026-06-04 18:16
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
Summary
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.
References
cna@python.orghttps://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0
cna@python.orghttps://github.com/python/cpython/commit/991224b1e8311c85f198f6dd8208bf8cff7fc26f
cna@python.orghttps://github.com/python/cpython/commit/ba785b88add96acbf403d65cb157fb2743a33a32
cna@python.orghttps://github.com/python/cpython/commit/c5512bd7c1dc28055660565275012766941d3066
cna@python.orghttps://github.com/python/cpython/issues/149079
cna@python.orghttps://github.com/python/cpython/pull/149080
cna@python.orghttps://mail.python.org/archives/list/security-announce@python.org/thread/PP5HB4K7727OBBM76KA2ILID76K3OZGZ/
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2026/06/03/15
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2026-3276",
  "lastModified": "2026-06-04T18:16:30.117",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "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",
          "version": "4.0",
          "vulnAvailabilityImpact": "LOW",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "cna@python.org",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-03T16:16:29.253",
  "references": [
    {
      "source": "cna@python.org",
      "url": "https://github.com/python/cpython/commit/6b505d1f41f8f3ea0fe5a4786d3a8fff1875cfc0"
    },
    {
      "source": "cna@python.org",
      "url": "https://github.com/python/cpython/commit/991224b1e8311c85f198f6dd8208bf8cff7fc26f"
    },
    {
      "source": "cna@python.org",
      "url": "https://github.com/python/cpython/commit/ba785b88add96acbf403d65cb157fb2743a33a32"
    },
    {
      "source": "cna@python.org",
      "url": "https://github.com/python/cpython/commit/c5512bd7c1dc28055660565275012766941d3066"
    },
    {
      "source": "cna@python.org",
      "url": "https://github.com/python/cpython/issues/149079"
    },
    {
      "source": "cna@python.org",
      "url": "https://github.com/python/cpython/pull/149080"
    },
    {
      "source": "cna@python.org",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/PP5HB4K7727OBBM76KA2ILID76K3OZGZ/"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "http://www.openwall.com/lists/oss-security/2026/06/03/15"
    }
  ],
  "sourceIdentifier": "cna@python.org",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ],
      "source": "cna@python.org",
      "type": "Secondary"
    }
  ]
}


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