PT-2025-49267 · Nextcloud · Nextcloud Enterprise Server+1

Published 2025-12-05 · Updated 2025-12-21 · CVE-2025-66512

Positive Technologies (AI Summary)

CVSS v3.1

6.1

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Nextcloud Server versions prior to 31.0.12 Nextcloud Server Enterprise versions prior to 31.0.12 Nextcloud Server versions prior to 32.0.3 Nextcloud Server Enterprise versions prior to 32.0.3

Description Nextcloud Server and Server Enterprise contain a missing sanitization that can allow malicious users to circumvent the content security policy. This occurs when a malicious user tricks another user into viewing a maliciously uploaded SVG file outside of the Nextcloud Server’s web page.

Recommendations Update Nextcloud Server to version 31.0.12 or later. Update Nextcloud Server Enterprise to version 31.0.12 or later. Update Nextcloud Server to version 32.0.3 or later. Update Nextcloud Server Enterprise to version 32.0.3 or later.

Exploit

Fix

XSS

Weakness Enumeration

CWE-80

CWE-79

Related Identifiers

CVE-2025-66512

GHSA-QCW2-P26M-9GC5

Affected Products

Nextcloud Server

Nextcloud Enterprise Server

References · 11

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66512.json · Exploit
• https://github.com/nextcloud/viewer/commit/5044a27d61bc40c0f134298d36af91f865335b63 · Patch
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qcw2-p26m-9gc5 · Vendor Advisory
• https://hackerone.com/reports/3357808 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2025-66512 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-66512 · Security Note
• https://github.com/nextcloud/viewer/pull/3023 · Note
• https://twitter.com/dailycve/status/1998492757313069209 · Twitter Post
• https://twitter.com/Cezar_H_Linux/status/2002702161411719564 · Twitter Post
• https://twitter.com/CVEnew/status/1996985621496115641 · Twitter Post
• https://t.me/cveNotify/145224 · Telegram Post