{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-66550 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2025-66550 yet. Limit exposure of the affected software until one is available.","what":"CVE-2025-66550 is a medium-severity vulnerability in nextcloud security-advisories, published on 5 Dec 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2025-66550 and fix it if it is affected.\n\nWhat it is: CVE-2025-66550 is a medium-severity vulnerability in nextcloud security-advisories, published on 5 Dec 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2025-66550 in the wild and no public exploit code.\n\nAffected product: nextcloud security-advisories. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-66550/ (Markdown: https://insights.sbomify.com/CVE-2025-66550/index.md)","id":"CVE-2025-66550","markdown":"https://insights.sbomify.com/CVE-2025-66550/index.md","name":"CVE-2025-66550","record":{"aliases":["GHSA-f29c-ppmv-8mcv"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Nextcloud Calendar app","requires_auth":"low_privilege","summary":"A malicious user can force the download of local server files via crafted calendar event attachments, bypassing user confirmation.","user_interaction":"required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"calendar","vendor":"nextcloud"}],"cvss":{"score":5.7,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-241","name":"Improper Handling of Unexpected Data Type"}],"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.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":false,"headline":"Nextcloud Calendar attachments of local files are offered to downloaded","id":"CVE-2025-66550","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"other","year":"2025"},"n_packages":0,"n_references":4,"next":{"headline":"Nextcloud Tables is missing an ownership check which allows moving columns into tables of other users","id":"CVE-2025-66551"},"packages":[],"prev":{"headline":"Nextcloud Desktop discloses information when attempting to lock a file inside a end-to-end encrypted directory","id":"CVE-2025-66549"},"products":["security-advisories"],"published":"2025-12-05","related":[{"cvss_score":5.3,"headline":"Command Injection in Appointment Emails for Nextcloud Calendar","id":"CVE-2022-24838","kev_date_added":null,"published":"2022-04-11"},{"cvss_score":4.8,"headline":"Nextcloud Calendar app used predictable proposal participant tokens","id":"CVE-2025-66511","kev_date_added":null,"published":"2025-12-05"},{"cvss_score":4.8,"headline":"Cross-site scripting in Nextcloud Calendar application","id":"CVE-2018-3763","kev_date_added":null,"published":"2018-07-05"},{"cvss_score":4.6,"headline":"Nextcloud Calendar's event create can create attachments that link to other websites","id":"CVE-2024-37316","kev_date_added":null,"published":"2024-06-14"},{"cvss_score":4.3,"headline":"Nextcloud: Calendar app leaked user identifiers via attendee suggestion endpoint","id":"CVE-2026-45286","kev_date_added":null,"published":"2026-06-01"},{"cvss_score":4.3,"headline":"Inviting excessive long email addresses to a calendar event makes the Nextcloud server unresponsive","id":"CVE-2023-45150","kev_date_added":null,"published":"2023-10-16"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2025-12-05","vendors":["nextcloud"]},"summary":"A malicious user can force the download of local server files via crafted calendar event attachments, bypassing user confirmation.","url":"https://insights.sbomify.com/CVE-2025-66550/"}