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TI-2026-53896 Aliases CVE-2026-77164GHSA-h4g5-x94v-qxqg

Server-side request forgery in nextcloud Server

Priority LOW 27CWE-918Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Information disclosure
Confidentiality · integrity · availability
High · None · None
Fix status
No fix listed

Attack profile from CVSS 3.0 · CNA. Fix status from CNA. Impact type from CWE-918 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00189 8th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudServer31.0.0 – 32.0.0—No fix listedCNA
  • Server Vendornextcloud Affected 31.0.0 – 32.0.0 Fixed in — No fix listed CNA

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-77164
  2. 2026-10-03 Alias added: GHSA-h4g5-x94v-qxqg

References

Other 1

  • TI-2026-18211 Windmill < 1.615.0 Operator Role Missing Authorization Checks RCE CVSS 4.0HIGH 8.7
  • TI-2023-14838 NextCloud Cookbook's pull-checks.yml workflow is vulnerable to OS Command Injection CVSS 3.1HIGH 8.8
  • TI-2022-08650 Command Injection in Appointment Emails for Nextcloud Calendar CVSS 3.1CRITICAL 9.8
  • TI-2023-20855 Users can delete external storage mount points CVSS 3.1HIGH 7.7
  • TI-2023-11091 Nextcloud download permissions can be changed by resharer CVSS 3.1HIGH 7.5
  • TI-2023-10624 Nextcloud Server vulnerable to SSRF via filter bypass due to lax checking on IPs CVSS 3.1MEDIUM 5.3
See all 401 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences