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TI-2026-81395 Aliases CVE-2026-77167

Nextcloud server federated share endpoint lets attackers inject rows

Priority LOW 39CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.0 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

Nextcloud server from 22.0.0 through 34.0.0 is affected. The federated share endpoint lets an unauthenticated remote attacker write arbitrary rows into the oc_share_external database table, and these rows persist with no automatic cleanup (CWE-400). The injected rows trigger three denial-of-service conditions that renew every 24 hours while the rows remain.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

Abusing the federated share endpoint, an attacker can write arbitrary rows into the oc_share_external database table. These rows persist indefinitely — there is no automatic cleanup mechanism. Three distinct denial-of-service conditions follow from this write primitive, all triggered from the same unauthenticated source and all self-renewing on a 24-hour cycle for as long as the injected rows remain in the database.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00367 30th 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
Yes
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
nextcloudserver22.0.0 – 34.0.0—No fix listedCNA
  • server Vendornextcloud Affected 22.0.0 – 34.0.0 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for Nextcloud server.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-27 Threatist record created from CVE-2026-77167
  2. 2026-10-28 Priority changed: MEDIUM → LOW
  3. 2026-10-29 Affected versions changed · Red Hat
  4. 2026-10-29 CVSS score added · Red Hat
  5. 2026-11-04 CISA SSVC decision points changed

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