{"api_version":"1","generated_at":"2026-09-18T09:13:04+00:00","cve":"CVE-2026-77164","urls":{"html":"https://cve.report/CVE-2026-77164","api":"https://cve.report/api/cve/CVE-2026-77164.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-77164","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-77164"},"summary":{"title":"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.","state":"PUBLISHED","assigner":"hackerone","published_at":"2026-09-18 02:17:07","updated_at":"2026-09-18 02:17:07"},"problem_types":["CWE-918","CWE-918 CWE-918 Server-Side Request Forgery (SSRF)"],"metrics":[{"version":"3.0","source":"support@hackerone.com","type":"Secondary","score":"6.2","severity":"MEDIUM","vector":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","data":{"version":"3.0","vectorString":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","baseScore":6.2,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE"}},{"version":"3.0","source":"CNA","type":"DECLARED","score":"6.2","severity":"MEDIUM","vector":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","data":{"baseScore":6.2,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.0"}}],"references":[{"url":"https://hackerone.com/reports/3303283","name":"https://hackerone.com/reports/3303283","refsource":"support@hackerone.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-77164","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-77164","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Nextcloud","product":"Server","version":"affected 31.0.0 32.0.0 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Balvant Chavda (0x0doteth)","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Server","vendor":"Nextcloud","versions":[{"lessThanOrEqual":"32.0.0","status":"affected","version":"31.0.0","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"Balvant Chavda (0x0doteth)"}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_0":{"baseScore":6.2,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","description":"CWE-918 Server-Side Request Forgery (SSRF)","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-09-18T01:26:04.650Z","orgId":"36234546-b8fa-4601-9d6f-f4e334aa8ea1","shortName":"hackerone"},"references":[{"url":"https://hackerone.com/reports/3303283"}]}},"cveMetadata":{"assignerOrgId":"36234546-b8fa-4601-9d6f-f4e334aa8ea1","assignerShortName":"hackerone","cveId":"CVE-2026-77164","datePublished":"2026-09-18T01:26:04.650Z","dateReserved":"2026-08-20T15:00:00.606Z","dateUpdated":"2026-09-18T01:26:04.650Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-18 02:17:07","lastModifiedDate":"2026-09-18 02:17:07","problem_types":["CWE-918","CWE-918 CWE-918 Server-Side Request Forgery (SSRF)"],"metrics":{"cvssMetricV30":[{"source":"support@hackerone.com","type":"Secondary","cvssData":{"version":"3.0","vectorString":"CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","baseScore":6.2,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":2.5,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"77164","Ordinal":"1","Title":"CVE-2026-77164","CVE":"CVE-2026-77164","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"77164","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"CVE-2026-77164"}]}}}