Auth bypass in Nextcloud Security-Advisories
CVE-2026-45159
Nextcloud is an open source content collaboration platform. From versions 1.15.0 to before 1.15.4, 1.16.0 to before 1.16.3, 1.17.0 to before 1.17.1, and 1.18.0 to before 1.18.1, a malicious user with access to an end-to-end encrypted files drop link was able to also drop files into other end-to-end encrypted folders of the share owner. Reading and modifying of other files was not possible. This issue has been patched in versions 1.15.4, 1.16.3, 1.17.1, 1.18.1, and 2.0.0-rc.7.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.5 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (26.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
- Nextcloud Security-Advisories — versions >= 1.15.0, < 1.15.4, >= 1.16.0, < 1.16.3, >= 1.17.0, < 1.17.1
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-45159?
- CVE-2026-45159 is a low-severity vulnerability in Nextcloud Security-Advisories, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 3.5/10. Published 2026-06-01.
- How severe is CVE-2026-45159?
- Low severity. CVSS v3 base score is 3.5 out of 10.