{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-55099", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-16T14:41:54.579Z", "datePublished": "2026-08-25T19:27:02.236Z", "dateUpdated": "2026-08-25T20:10:56.453Z"}, "containers": {"cna": {"title": "icalendar: Algorithmic Complexity in Equality", "problemTypes": [{"descriptions": [{"cweId": "CWE-400", "lang": "en", "description": "CWE-400: Uncontrolled Resource Consumption", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-407", "lang": "en", "description": "CWE-407: Inefficient Algorithmic Complexity", "type": "CWE"}]}], "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"}}], "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"}], "affected": [{"vendor": "collective", "product": "icalendar", "versions": [{"version": ">= 7.1.0, < 7.1.3", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-25T19:27:02.236Z"}, "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."}], "source": {"advisory": "GHSA-cv84-9p8j-fj68", "discovery": "UNKNOWN"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "http://www.openwall.com/lists/oss-security/2026/06/23/8"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-08-25T20:10:56.453Z"}}]}}

{}

{"affected": [{"affectedData": [{"product": "icalendar", "vendor": "collective", "versions": [{"status": "affected", "version": ">= 7.1.0, < 7.1.3"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "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."}], "id": "CVE-2026-55099", "lastModified": "2026-08-25T20:16:56.940", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-08-25T20:16:56.940", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/collective/icalendar/commit/b6b2608ae3af6de40695b4e40f71847485aa0b49"}, {"source": "security-advisories@github.com", "url": "https://github.com/collective/icalendar/commit/cad40cd112c93fd142ec12cc5b37445a849b8a79"}, {"source": "security-advisories@github.com", "url": "https://github.com/collective/icalendar/releases/tag/v7.1.3"}, {"source": "security-advisories@github.com", "url": "https://github.com/collective/icalendar/security/advisories/GHSA-cv84-9p8j-fj68"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-407"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}