Upstream information
Description
Circles' remote-instance signature verification fetches the attacker-supplied keyId URL before trust in the remote instance is established, and explicitly allows local/private addresses for this request, bypassing Nextcloud's core SSRF protections. The public, unauthenticated endpoints POST /apps/circles/event/ and POST /apps/circles/incoming/ reach this code path, allowing any unauthenticated user to force the server to issue a GET request to an internal address.The response body of the internal request is never returned to the requester, so this is blind SSRF: an attacker can determine whether an internal service is reachable, but cannot read its response contents through this endpoint alone.
SUSE information
Overall state of this security issue: Does not affect SUSE products
This issue is currently rated as having moderate severity.
| CVSS detail | CNA (HackerOne) |
|---|---|
| Base Score | 6.2 |
| Vector | CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | High |
| Integrity Impact | None |
| Availability Impact | None |
| CVSSv3 Version | 3 |
SUSE Timeline for this CVE
CVE page created: Wed Sep 23 15:44:24 2026CVE page last modified: Wed Sep 23 15:44:24 2026