---
id: CVE-2026-77167
title: >-
  Abusing the federated share endpoint, an attacker can write arbitrary rows
  into the oc_share_external database table
summary: >-
  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 …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-400
vendor: Nextcloud
product: server
affected:
  - server >= 22.0.0 <= 34.0.0
published: '2026-10-27'
updated: '2026-10-27'
sourceUpdated: '2026-10-27T16:15:34.778Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-77167'
references:
  - url: 'https://hackerone.com/reports/3679640'
tags:
  - cve.org
ingestedAt: '2026-10-27T16:32:34.401Z'
---

## Overview

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.

## Affected

- `server >= 22.0.0 <= 34.0.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.