Vulnerability in Nextcloud (CVE-2026-45285)
Summary
Vulnerability in Nextcloud (CVE-2026-45285). Confidential information can be exposed externally.
Original description
The description as published by the source.
Nextcloud is an open source content collaboration platform. From versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, when a user shares a folder or file with a Nextcloud Team that includes an external member (a person added via email address who does not have a Nextcloud account), the system automatically creates a public link for that external member. This public link is not displayed in the share section of the folder, so the folder owner has no knowledge of its existence. It is sent via email to the external member. It grants the same permissions (read, write, delete, reshare, download) as the Team’s access. An attacker who receives or intercepts this link can access, modify, delete, reshare, and download all data in the shared folder without any further authentication. The folder owner cannot see or revoke the link through the normal sharing interface. This issue has been patched in versions 32.0.9 and 33.0.3.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-45285 has been found in Nextcloud.
Confidential information can be exposed externally. CVSS score: 6.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Nextcloud CVE-2026-45285" on the vendor's site.
CVE-2026-45285 (Nextcloud) — CWE-862 / CVSS v3 6.4
Attack vector: remote (network-reachable)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-862) exists in Nextcloud.
Check the vendor advisory for the affected versions of Nextcloud.
Severity: Medium (CVSS 6.4/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Nextcloud' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Nextcloud' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Nextcloudを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。