{"id":"CVE-2026-77164","aliases":["BIT-nextcloud-2026-77164","EUVD-2026-82621","GHSA-h4g5-x94v-qxqg"],"status":"published","title":"Circles' remote-instance signature verification fetches the attacker-supplied keyId URL before...","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.\n\nThe 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.","severity":{"version":"3.0","score":6.2,"vector":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00189,"percentile":0.08572,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-918"],"published":"2026-09-18T01:26:04Z","modified":"2026-09-25T14:15:15Z","fixes":[{"ecosystem":"Bitnami","package":"nextcloud","fixed_in":["34.0.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"nextcloud","ranges":[{"type":"SEMVER","events":[{"introduced":"31.0.0"},{"fixed":"34.0.1"}]}]}],"products":[{"vendor":"devolutions","product":"server"},{"vendor":"nextcloud","product":"server"}],"references":[{"url":"https://hackerone.com/reports/3303283","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-77164","tags":["web"]},{"url":"https://github.com/advisories/GHSA-h4g5-x94v-qxqg"}],"sources":{"cve":[{"id":"CVE-2026-77164","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.\n\nThe 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.","status":"published","published":"2026-09-18T01:26:04.65Z","modified":"2026-09-18T19:41:07.4Z","cvss":[{"version":"3.0","score":6.2,"vector":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:20:15.712761Z"}],"euvd":[{"id":"EUVD-2026-82621","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.\n\nThe 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.","status":"published","published":"2026-09-18T01:26:04Z","modified":"2026-09-18T19:41:07Z","cvss":[{"version":"3.0","score":6.2,"vector":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T17:28:07.574446Z"}],"ghsa":[{"id":"GHSA-h4g5-x94v-qxqg","title":"Circles' remote-instance signature verification fetches the attacker-supplied keyId URL before...","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.\n\nThe 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.","status":"published","published":"2026-09-18T03:30:25Z","modified":"2026-09-18T03:30:26Z","cvss":[{"version":"3.0","score":6.2,"vector":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:12:08.779152Z"}],"nvd":[{"id":"CVE-2026-77164","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.\n\nThe 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.","status":"published","published":"2026-09-18T02:17:07.51Z","modified":"2026-09-18T20:17:22.273Z","cvss":[{"version":"3.0","score":6.2,"vector":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:49.70655Z"}],"osv":[{"id":"BIT-nextcloud-2026-77164","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.\n\nThe 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.","status":"published","published":"2026-09-25T12:27:07.203Z","modified":"2026-09-25T14:15:15.164592754Z","updated_at":"2026-11-02T15:28:34.007508Z"}]}}