PT-2025-49268 · Nextcloud+1 · Nextcloud Server+2

Published 2025-12-05 · Updated 2026-01-29 · CVE-2025-66547

Positive Technologies (AI Summary)

CVSS v3.1

4.3

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Nextcloud Server and Enterprise Server versions prior to 31.0.1

Description Non-privileged users can modify tags on files they should not have access to through bulk tagging. This affects a self-hosted personal cloud system.

Recommendations Update to version 31.0.1 or later.

Exploit

Fix

LPE

IDOR

Weakness Enumeration

CWE-639

Related Identifiers

BDU:2026-03382

CVE-2025-66547

GHSA-HQ6C-R898-FGF2

Affected Products

Nextcloud Enterprise Server

Nextcloud Server

Red Os

References · 16

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66547.json · Exploit
• https://github.com/nextcloud/server/commit/b44f1568f2dc97c746281d99e2342ad679e3d8a9 · Patch
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hq6c-r898-fgf2 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-66547 · Security Note
• http://repo.red-soft.ru/redos/8.0/x86_64/updates · Vendor Advisory
• https://hackerone.com/reports/3040887 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-03382 · Security Note
• https://osv.dev/vulnerability/CVE-2025-66547 · Vendor Advisory
• https://github.com/nextcloud/server/issues/51247 · Note
• https://github.com/nextcloud/server/pull/51288 · Note
• https://redos.red-soft.ru/support/secure/uyazvimosti/support/secure/uyazvimosti-red-os-8-0/uyazvimost-nextcloud-cve-2025-66547-8.0 · Note
• https://t.me/cveNotify/145226 · Telegram Post
• https://redos.red-soft.ru/support/secure/uyazvimosti/support/secure/uyazvimosti/uyazvimost-nextcloud-cve-2025-66547-7.3 · Note
• https://twitter.com/VulmonFeeds/status/1997012574286520577 · Twitter Post
• https://twitter.com/dailycve/status/1998484893521613123 · Twitter Post