CVE-2026-53521

Deferred Deferred - Pending Action

DDNS Profile ID Injection in Nezha Monitoring

Publication date: 2026-06-12

Last updated on: 2026-06-15

Assigner: GitHub, Inc.

Description

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 2.0.14 to before version 2.1.0, PATCH /server/{id} accepts and persists nonexistent ddns_profiles IDs for a member-owned server. If another user later creates a DDNS profile with one of those IDs, the DDNS worker resolves the stored ID and dispatches an update using the other user's DDNS profile configuration in the context of the attacker's server. This issue has been patched in version 2.1.0.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-06-12

Last Modified

2026-06-15

Generated

2026-07-03

AI Q&A

2026-06-13

EPSS Evaluated

2026-07-02

NVD

CVE-2026-53521

Affected Vendors & Products

Vendor	Product	Version / Range
nezha_monitoring	nezha_monitoring	From 2.0.14 (inc) to 2.1.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-863	The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

Executive Summary

This vulnerability exists in Nezha Monitoring versions from 2.0.14 up to but not including 2.1.0. The PATCH /server/{id} endpoint accepts and stores IDs for ddns_profiles that do not actually exist for a member-owned server. If another user later creates a DDNS profile using one of those stored nonexistent IDs, the DDNS worker will resolve that stored ID and send updates using the other user's DDNS profile configuration, but in the context of the attacker’s server. This means an attacker can manipulate DDNS profile associations to cause unintended updates.

This issue was fixed in version 2.1.0.

Impact Analysis

The vulnerability can lead to unauthorized use of another user's DDNS profile configuration in the context of the attacker's server. This can cause incorrect or malicious updates to be dispatched, potentially disrupting monitoring operations or causing data integrity issues.

According to the CVSS score of 6.4 (medium severity), the impact includes limited integrity and availability loss, meaning attackers can alter information or cause partial service disruption without gaining full control.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade Nezha Monitoring to version 2.1.0 or later, where the issue has been patched.

Hi! I’m here to help you understand CVE-2026-53521. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70