Authorization Flaw in github.com/nezhahq/nezha (CVE-2026-53521)
Summary
Vulnerability in github.com/nezhahq/nezha (CVE-2026-53521). Risk of unauthorized operations or information disclosure. Exploitable via PATCH /server/{id}. Mitigation: upgrade to 2.1.0 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-53521 has been found in github.com/nezhahq/nezha.
Attackers can target a specific entry point like PATCH /server/{id} over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.4/10.
What to do: upgrade github.com/nezhahq/nezha to 2.1.0 or later.
If unsure, ask your IT team or search "github.com/nezhahq/nezha CVE-2026-53521" on the vendor's site.
CVE-2026-53521 (github.com/nezhahq/nezha) — CWE-863 / CVSS v3 6.4
Attack vector: remote (network-reachable) / no user interaction
Attack surface: PATCH /server/{id} / ddns_profiles / CheckPermission / updateServer
Patched: 2.1.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Incorrect authorization (CWE-863) exists in github.com/nezhahq/nezha. Attackers reach the vulnerable code path via PATCH /server/{id}.
Check the vendor advisory for the affected versions of github.com/nezhahq/nezha. Attack surface: PATCH /server/{id} / ddns_profiles / CheckPermission / updateServer.
Severity: Medium (CVSS 6.4/10). Risk of unauthorized operations or information disclosure.
Update to 2.1.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual PATCH /server/{id} requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/nezhahq/nezha' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/nezhahq/nezha' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/nezhahq/nezhaを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'PATCH /server/{id}' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
PATCH /server/{id}への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade github.com/nezhahq/nezha to 2.1.0ステージング環境で 2.1.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against PATCH /server/{id} on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com