CVE-2025-66550

Signals

NVD · CVE-2026-64604 · In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Grab vmcs12 on CR8 interception update iff vCPU is in guest mode When updating CR8NVD · CVE-2026-64603 · In the Linux kernel, the following vulnerability has been resolved: platform/x86: intel-hid: Protect ACPI notify handler against recursion Since commit e2ffcda1NVD · CVE-2026-64602 · In the Linux kernel, the following vulnerability has been resolved: iio: adc: spear: Initialize completion before requesting IRQ In the report from Jaeyoung ChuNVD · CVE-2026-64601 · In the Linux kernel, the following vulnerability has been resolved: ALSA: us144mkii: capture_urb_complete: redundant usb_anchor_urb corrupts anchor list on eachCISA KEV · CVE-2026-63077 · 9.8 · JetBrains TeamCity Deserialization of Untrusted Data Vulnerability · Added 2026-08-05 · Due 2026-08-08CISA KEV · CVE-2026-18556 · 7.4 · N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability · Added 2026-08-04 · Due 2026-08-07NVD · CVE-2026-64604 · In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Grab vmcs12 on CR8 interception update iff vCPU is in guest mode When updating CR8NVD · CVE-2026-64603 · In the Linux kernel, the following vulnerability has been resolved: platform/x86: intel-hid: Protect ACPI notify handler against recursion Since commit e2ffcda1NVD · CVE-2026-64602 · In the Linux kernel, the following vulnerability has been resolved: iio: adc: spear: Initialize completion before requesting IRQ In the report from Jaeyoung ChuNVD · CVE-2026-64601 · In the Linux kernel, the following vulnerability has been resolved: ALSA: us144mkii: capture_urb_complete: redundant usb_anchor_urb corrupts anchor list on eachCISA KEV · CVE-2026-63077 · 9.8 · JetBrains TeamCity Deserialization of Untrusted Data Vulnerability · Added 2026-08-05 · Due 2026-08-08CISA KEV · CVE-2026-18556 · 7.4 · N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability · Added 2026-08-04 · Due 2026-08-07

CVE Database · CVE-2025-66550

CVE-2025-66550

· MEDIUMAnalyzed

CVSS v3.1

5.7

EPSS

0.33%

Published

Dec 5, 2025

Modified

Dec 10, 2025

Public PoC / Exploit

All weaponized →

No public PoC or exploit code indexed for this CVE.

Links to public security research (Exploit-DB, Nuclei, Trickest, GitHub) for defensive use only.

Description

Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.17 and 5.2.4, when a malicious user creates a calendar event with a crafted attachment that links to a download link of a file on the same Nextcloud server, the file would be downloaded without the user confirming the action. This vulnerability is fixed in 4.7.17 and 5.2.4.

CVSS Vector

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

Weaknesses (CWE)

CWE-241

Affected Products (2)

nextcloud · calendar (up to 4.7.17)vulnerable

nextcloud · calendar (up to 5.2.4)vulnerable

References (4)

https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769

Patch

https://github.com/nextcloud/calendar/pull/6971

Issue Tracking

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv

PatchVendor Advisory

https://hackerone.com/reports/3112033

Issue TrackingVendor Advisory

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