{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "6.1.0"
              },
              {
                "fixed": "7.2.2"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "a492d69437892bca718658487b18c632a71371c4"
            },
            {
              "fixed": "157f85137c65565a308bbcf4fdcc7d8ebce01267"
            },
            {
              "fixed": "cddd37226adbc52cca52a399f61d38a378221219"
            },
            {
              "fixed": "ad87bcf719fde8088a77c724bc2ae8f09545e0e4"
            }
          ],
          "repo": "https://github.com/collective/icalendar",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qjcq-q7h7-r74v"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-400",
      "CWE-834"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77399.json"
  },
  "details": "icalendar is an RFC 5545 compatible parser and generator of iCalendar files for Python. From 6.1.0 until 7.2.2, vInt.from_ical accepts an attacker-controlled VALARM REPEAT value and applications that request alarm times can eagerly expand it without an application-level limit. Alarms.times and Alarms.active reach the unbounded expansion in versions starting with 6.1.0, while Alarm.triggers adds a second affected path starting with 7.0.0. Parsing alone does not trigger the issue, but accessing these properties can consume excessive CPU time and heap memory and terminate or stall a service. This issue is fixed in version 7.2.2.",
  "id": "CVE-2026-77399",
  "modified": "2026-09-25T03:30:25.486879523Z",
  "published": "2026-09-22T18:58:56.647Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/collective/icalendar/releases/tag/v7.2.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77399.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/collective/icalendar/security/advisories/GHSA-qjcq-q7h7-r74v"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-77399"
    },
    {
      "type": "FIX",
      "url": "https://github.com/collective/icalendar/commit/157f85137c65565a308bbcf4fdcc7d8ebce01267"
    },
    {
      "type": "FIX",
      "url": "https://github.com/collective/icalendar/commit/cddd37226adbc52cca52a399f61d38a378221219"
    },
    {
      "type": "FIX",
      "url": "https://github.com/collective/icalendar/pull/1571"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "icalendar: Denial of service via unbounded VALARM REPEAT expansion"
}