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CVE-2026-53521

MEDIUMCVSS 6.4/10EPSS 0.23%

Last modified

CVE-2026-53521 is a medium-severity vulnerability rated 6.4/10 on the CVSS scale. 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. EPSS estimates a 0.23% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
6.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L

EPSS Probability
0.23%

13.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-53521?
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.
How severe is CVE-2026-53521?
CVE-2026-53521 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.23% probability of exploitation in the next 30 days.
How do I fix CVE-2026-53521?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-53521?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST