{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-08-25T20:10:56.453Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/06/23/8"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55099",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-26T15:05:19.449076Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-26T15:05:26.062Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/collective/icalendar/security/advisories/GHSA-cv84-9p8j-fj68"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "icalendar",
          "vendor": "collective",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 7.1.0, \u003c 7.1.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "icalendar is an RFC 5545 compatible parser and generator of iCalendar files for Python. From 7.1.0 until 7.1.3, the Component equality method in src/icalendar/cal/component.py compares nested subcomponents with two membership loops, and each membership test invokes the same method on child components, causing O(2^n) work relative to nesting depth. Component.from_ical accepts arbitrarily nested BEGIN:VEVENT blocks without a depth limit, so an attacker can submit a sub-kilobyte .ics file containing equal nested subtrees and trigger the cost when an application performs equality, inequality, membership, deduplication, test-assertion, round-trip, or normalization comparisons. Parsing alone does not trigger the issue, and comparisons that differ early short-circuit, but a few hundred bytes can pin a CPU core for minutes or indefinitely, causing denial of service in calendar sync or import endpoints, invite processing, and other comparison paths. This issue is fixed in version 7.1.3."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "CWE-400: Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-407",
              "description": "CWE-407: Inefficient Algorithmic Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T19:27:02.236Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/collective/icalendar/security/advisories/GHSA-cv84-9p8j-fj68",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/collective/icalendar/security/advisories/GHSA-cv84-9p8j-fj68"
        },
        {
          "name": "https://github.com/collective/icalendar/commit/b6b2608ae3af6de40695b4e40f71847485aa0b49",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/collective/icalendar/commit/b6b2608ae3af6de40695b4e40f71847485aa0b49"
        },
        {
          "name": "https://github.com/collective/icalendar/commit/cad40cd112c93fd142ec12cc5b37445a849b8a79",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/collective/icalendar/commit/cad40cd112c93fd142ec12cc5b37445a849b8a79"
        },
        {
          "name": "https://github.com/collective/icalendar/releases/tag/v7.1.3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/collective/icalendar/releases/tag/v7.1.3"
        }
      ],
      "source": {
        "advisory": "GHSA-cv84-9p8j-fj68",
        "discovery": "UNKNOWN"
      },
      "title": "icalendar: Algorithmic Complexity in Equality"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55099",
    "datePublished": "2026-08-25T19:27:02.236Z",
    "dateReserved": "2026-06-16T14:41:54.579Z",
    "dateUpdated": "2026-08-26T15:05:26.062Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}