CVE-2025-66511

Nextcloud Calendar app used predictable proposal participant tokens

CVSS 4.8 MEDIUMEPSS 0.2%CWE-330

Vexday Risk Score

13Bajo

Decisión SSVC (CISA)

Track

Sin señal de explotación → monitorear

CVSS 4.8EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —

Ciclo de vida

05 dic 2025Publicada en NVD

Recomendación: Monitorear — sin señal de explotación por ahora.

Nextcloud Calendar is a calendar app for Nextcloud. Prior to 6.0.3, the Calendar app generates participant tokens for meeting proposals using a hash function, allowing an attacker to compute valid participant tokens, which allowed them to request details and submit dates in meeting proposals. The tokens are not purely random generated. This vulnerability is fixed in 6.0.3.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Productos afectados

nextcloud · security-advisories

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Referencias

https://github.com/nextcloud/calendar/commit/8de14ae87f321f5f09280d9895a27d54d24f33fb https://github.com/nextcloud/calendar/pull/7659 https://github.com/nextcloud/security-advisories/security/advisories/GHSA-whm3-vv55-gf27 https://hackerone.com/reports/3385434