Security Digest · Vulnerability record
CVE-2026-53519: Nezha Monitoring: Pre-auth path traversal via /dashboard.. prefix confusion leaks jwt_secret_key
Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool.
CVSS 9.1 Critical EPSS 2.3% · p83
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 2.3%, percentile 83: FIRST’s model estimates a 2.3% chance of exploitation activity in the next 30 days, higher than 83% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
github.com/nezhahq/nezha(Go) < 2.0.13, fixed in 2.0.13. Check your lockfile, including transitive dependencies.
What it is
Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. Prior to version 2.0.13, 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. This issue has been patched in version 2.0.13.
From the GitHub advisory
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 — r.NoRoute(fallbackToFrontend(frontendDist)) — so every URL not matched by an earlier route reaches it, including pre-auth.
Path math (verified, see appendix)
Weakness type: CWE-22.
Product: github.com/nezhahq/nezha (Go) · Assigned by: GitHub_M · Published: 2026-06-12
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/nezhahq/nezha | < 2.0.13 | 2.0.13 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| nezhahq | nezha | < 2.0.13 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 2.29% probability of exploitation activity in the next 30 days; percentile 83.
Timeline
- — CVE record published by GitHub_M
- — CVE record last updated
- — GitHub-reviewed advisory GHSA-5c25-7vpj-9mqh published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-5c25-7vpj-9mqh github.com
- CVE.org record CVE-2026-53519 cve.org
- NVD entry CVE-2026-53519 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com