VDB-427432 · CVE-2026-77167 · WID-SEC-2026-4185

Nextcloud Server up to 34.0.0 Federated Share Endpoint denial of service

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.0	$0-$5k	1.30-

Summaryinfo

A vulnerability described as critical has been identified in Nextcloud Server up to 34.0.0. Impacted is an unknown function of the component Federated Share Endpoint. Executing a manipulation can lead to denial of service. This vulnerability is tracked as CVE-2026-77167. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in Nextcloud Server up to 34.0.0 and classified as critical. This vulnerability affects an unknown code block of the component Federated Share Endpoint. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at hackerone.com. This vulnerability was named CVE-2026-77167 since 08/20/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-4185). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

Nextcloud Nextcloud

Productinfo

Type

Cloud Software

Vendor

Nextcloud

Name

Server

Version

34.0

License

open-source

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.0
VulDB Meta Temp Score: 7.0

VulDB Base Score: 6.5
VulDB Temp Score: 6.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (hackerone): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/20/2026 CVE reserved
10/27/2026 +68 days Advisory disclosed
10/27/2026 +0 days VulDB entry created
10/28/2026 +1 days VulDB entry last update

Sourcesinfo

Advisory: hackerone.com
Status: Not defined

CVE: CVE-2026-77167 (🔒)
GCVE (CVE): GCVE-0-2026-77167
GCVE (VulDB): GCVE-100-427432
CERT Bund: WID-SEC-2026-4185 - Nextcloud (Server, Tables, Whiteboard, Files Confidential, Collectives, Richdocuments): Mehrere Schwachstellen

Entryinfo

Created: 10/27/2026 17:35
Updated: 10/28/2026 01:23
Changes: 10/27/2026 17:35 (62), 10/28/2026 01:23 (7)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.