CVE-2026-45286: nextcloud calendar
Vulnerability summary
CVE-2026-45286 is a medium (CVSS 4.3) vulnerability in nextcloud calendar. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.2% of scored vulnerabilities. 1 public exploit is recorded.
Timeline
- 01-06-2026PublishedVulnerability first disclosed.
- 01-06-2026Last modifiedVulnerability information updated.
Description
Nextcloud is an open source content collaboration platform. From versions 5.5.13 to before 5.5.17, and 6.2.0 to before 6.2.3, an authenticated user can enumerate users on the same Nextcloud instance by using the Calendar app's endpoint for suggesting attendees. The sharing restrictions, applied to other endpoints, were not effective here. This issue has been patched in versions 5.5.17 and 6.2.3.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
EPSS trend
Probability
0.46%
Chance of exploitation in the next 30 days
Percentile
38%
Versus all other CVEs
30-day change
+0.17 pp
From 0.28% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundCalendar
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Nextcloud2 products
- calendar≥ 5.5.13, < 5.5.17 | ≥ 6.2.0, < 6.2.3
- security-advisories≥ 5.5.13, < 5.5.17 | ≥ 6.2.0, < 6.2.3
1 vendor · 2 products
References
4 links- github.com/nextcloud/security-advisories/security/advisories/GHSA-r697-74m9-gvf2X Refsource CONFIRMMitigationVendor Advisory