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    2 vulnerabilities by collective

    CVE-2026-55099 (GCVE-0-2026-55099)

    Vulnerability from nvd – Published: 2026-08-25 19:27 – Updated: 2026-08-26 15:05
    VLAI
    Title
    icalendar: Algorithmic Complexity in Equality
    Summary
    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.
    Severity
    7.5 (High)
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    SSVC
    Exploitation: poc Automatable: yes Technical Impact: partial
    CISA Coordinator · CISA-ADP (v2.0.3)
    Decision recorded 2026-08-26 15:05 UTC
    CWE
    • CWE-400 - Uncontrolled Resource Consumption
    • CWE-407 - Inefficient Algorithmic Complexity
    Assigner
    References
    Impacted products
    Vendor Product Version
    collective icalendar Affected: >= 7.1.0, < 7.1.3
    		Create a notification for this product.
    Show details on NVD website
    To clipboard 

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    CVE-2026-55099 (GCVE-0-2026-55099)

    Vulnerability from cvelistv5 – Published: 2026-08-25 19:27 – Updated: 2026-08-26 15:05
    VLAI
    Title
    icalendar: Algorithmic Complexity in Equality
    Summary
    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.
    Severity
    7.5 (High)
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    SSVC
    Exploitation: poc Automatable: yes Technical Impact: partial
    CISA Coordinator · CISA-ADP (v2.0.3)
    Decision recorded 2026-08-26 15:05 UTC
    CWE
    • CWE-400 - Uncontrolled Resource Consumption
    • CWE-407 - Inefficient Algorithmic Complexity
    Assigner
    References
    Impacted products
    Vendor Product Version
    collective icalendar Affected: >= 7.1.0, < 7.1.3
    		Create a notification for this product.
    Show details on NVD website
    To clipboard 

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