CVE-2026-45159
CVE-2026-45159 is a low-severity vulnerability with a CVSS 3.x base score of 3.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-639.
Key facts
- Severity: Low (CVSS 3.x base score 3.5)
- EPSS exploit prediction: 0% (10th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-33677
- Weakness: CWE-639
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-45159?
- CVE-2026-45159 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2026-45159 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-45159?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-45159 have an EU (EUVD) identifier?
- Yes. CVE-2026-45159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-33677.
- When was CVE-2026-45159 published?
- CVE-2026-45159 was published on 2026-06-01 and last updated on 2026-06-17.
References
- https://github.com/nextcloud/end_to_end_encryption/pull/1395
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-p3qw-7gwx-wg24
- https://hackerone.com/reports/3304830
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