SSRF protection bypass in calendar subscriptions (NC-SA-2020-014)
12th December 2019
Risk level: Low
CVSS v3 Base Score: 6.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L)
CWE: Server-Side Request Forgery (SSRF) (CWE-918)
HackerOne report: 736867
Description
A missing check for IPv4 nested inside IPv6 in Nextcloud server 17.0.1 allowed a SSRF when subscribing to a malicious calendar URL.
Affected Software
- Nextcloud Server < 17.0.2 (CVE-2020-8138)
- Nextcloud Server < 16.0.7 (CVE-2020-8138)
- Nextcloud Server < 15.0.14 (CVE-2020-8138)
Action Taken
The error has been fixed.
Resolution
It is recommended that the Nextcloud server is upgraded to 17.0.2.
Acknowledgements
The Nextcloud team thanks the following people for their research and responsible disclosure of the above advisory:
This advisory is licensed CC BY-SA 4.0.