Nezha Monitoring: Pre-auth path traversal via /dashboard.. prefix confusion leaks jwt_secret_key

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-53519: 1.93% estimated exploitation activity in the next 30 days; percentile 80.00 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary fallbackToFrontend in the dashboard's NoRoute handler treats any URL whose raw string starts with /dashboard as an admin-frontend asset request. The check uses strings.HasPrefix, not a path-segment match, so the input /dashboard../data/config.yaml is accepted; strings.TrimPrefix leaves ../data/config.yaml; and path.Join("admin-dist", "../data/config.yaml") normalizes to data/config.yaml — which os.Stat finds and http.ServeFile returns. No authentication required. In default deployments (the values shipped in model/config.go and the layout shipped in the project Dockerfile) data/config.yaml contains the HS256 jwtsecretkey used by cmd/dashboard/controller/jwt.go to sign every dashboard session cookie. A unauth attacker reads that secret, forges an admin JWT, and signs in as any user — full dashboard takeover from one GET request. Details Root cause fallbackToFrontend is wired as the catch-all at cmd/dashboard/controller/controller.go:157 —…

Published by the source

26 Jun 2026, 23:03 UTC

Last modified by the source

26 Jun 2026, 23:03 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-5c25-7vpj-9mqh

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# Patch Next advisory brief: CVE-2026-53519

Advisory: Nezha Monitoring: Pre-auth path traversal via /dashboard.. prefix confusion leaks jwt_secret_key
IDs: CVE-2026-53519, GHSA-5c25-7vpj-9mqh
Record: https://patchnext.com/advisories/cve-2026-53519 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/nezhahq/nezha 2.0.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/nezhahq/nezha: affected < 2.0.13; fixed in 2.0.13

## Suggested inspection (read-only)
- Go github.com/nezhahq/nezha: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/nezhahq/nezha.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-5c25-7vpj-9mqh (GitHub-reviewed advisory GHSA-5c25-7vpj-9mqh lists affected ranges: Go github.com/nezhahq/nezha >=0 <2.0.13)

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