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CVE-2026-53521 nezhahq CVE debrief

Nezha Monitoring is a self-hostable, lightweight tool for monitoring servers and websites. A vulnerability exists in versions 2.0.14 to before 2.1.0, where the PATCH /server/{id} endpoint 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.

Vendor
nezhahq
Product
nezha
CVSS
MEDIUM 6.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-06-15
Advisory published
2026-06-12
Advisory updated
2026-06-15

Who should care

Users of Nezha Monitoring, particularly those who have not upgraded to version 2.1.0, should be aware of this vulnerability and take necessary precautions.

Technical summary

The vulnerability exists in the PATCH /server/{id} endpoint of Nezha Monitoring, where it accepts and persists nonexistent ddns_profiles IDs for a member-owned server. This allows an attacker to potentially dispatch an update using another user's DDNS profile configuration.

Defensive priority

MEDIUM

Recommended defensive actions

  • Upgrade to Nezha Monitoring version 2.1.0 or later.
  • Review and restrict access to the PATCH /server/{id} endpoint.
  • Monitor for suspicious activity related to DDNS profile updates.

Evidence notes

The CVE-2026-53521 vulnerability has a CVSS score of 6.4 and is classified as MEDIUM severity. The vulnerability was published on 2026-06-12T22:16:52.230Z and has not been modified since.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53521 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53521

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-53521 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53521

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.