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CVE-2026-55956

Status: AnalyzedMedium (6.5)—

Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected.

Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Apache — Tomcat

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-55956",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55956",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-06-30T13:23:02.427983Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.5,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security@apache.org",
      "affectedData": [
        {
          "vendor": "Apache Software Foundation",
          "product": "Apache Tomcat",
          "versions": [
            {
              "status": "affected",
              "version": "11.0.0-M1",
              "versionType": "semver",
              "lessThanOrEqual": "11.0.22"
            },
            {
              "status": "affected",
              "version": "10.1.0-M1",
              "versionType": "semver",
              "lessThanOrEqual": "10.1.55"
            },
            {
              "status": "affected",
              "version": "9.0.0.M1",
              "versionType": "semver",
              "lessThanOrEqual": "9.0.118"
            },
            {
              "status": "affected",
              "version": "8.5.0",
              "versionType": "semver",
              "lessThanOrEqual": "8.5.100"
            },
            {
              "status": "affected",
              "version": "7.0.0",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.109"
            },
            {
              "status": "unknown",
              "version": "0",
              "lessThan": "7.0.0",
              "versionType": "semver"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-06-29T21:16:45.597",
  "references": [
    {
      "url": "https://lists.apache.org/thread/dcjdcnnnww9hhdm016hr0l7hpw1bzjfp",
      "tags": [
        "Vendor Advisory",
        "Mailing List"
      ],
      "source": "security@apache.org"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2026/06/29/25",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security@apache.org",
      "description": [
        {
          "lang": "en",
          "value": "CWE-285"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint.\n\nThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected.\n\nUsers are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue."
    }
  ],
  "lastModified": "2026-07-02T19:03:30.203",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "5BB3B349-8AB6-4C07-B186-888CAFB1609E",
              "versionEndExcluding": "9.0.119"
            },
            {
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              "vulnerable": true,
              "matchCriteriaId": "4A8C20B4-DBE1-4890-AD5E-D5EABB6B739D",
              "versionEndExcluding": "10.1.56",
              "versionStartIncluding": "10.1.0"
            },
            {
              "criteria": "cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C43AD2A0-8785-4A37-AAAE-347B1E0463F1",
              "versionEndExcluding": "11.0.23",
              "versionStartIncluding": "11.0.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@apache.org"
}