Nezha Monitoring: RoleMember can run shell on every server (cross-tenant RCE) via POST /api/v1/cron

published 2026-05-23 5 mo ago modified 2026-10-25 14 d ago also GHSA-99gv-2m7h-3hh9 , GO-2026-5282 , EUVD-2026-36591

cvss: 9.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits: 0; none known

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.4.0 to before version 2.0.8, a RoleMember user can create a scheduled cron task with Cover=CronCoverAll, Servers=[] and an arbitrary Command. At every tick of the scheduler, the dashboard pushes that command to every server in the global ServerShared map — including servers that belong to other tenants (admin's servers, other members' servers). Each agent runs the command and returns the output, which is then sent to the attacker's own NotificationGroup → attacker-controlled webhook. This issue has been patched in version 2.0.8.

Patch / fix

fixed in 1 distros 1

go github.com/nezhahq/nezha 1.14.15-0.20260517022419-d7526351cf97

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 4 mo ago (2026-06-15)

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/nezhahq/nezha/security/advisories/GHSA-99gv-2m7h-3hh9 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
GitHub	3.1	9.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
go	github.com/nezhahq/nezha	>=1.4.0, <1.14.15-0.20260517022419-d7526351cf97	1.14.15-0.20260517022419-d7526351cf97

Affected products

nezhahq nezha

Classification

Weakness

CWE-78 Improper Neutralization of Special Elements used in an OS Command
CWE-269 Improper Privilege Management
CWE-862 Missing Authorization

References

github.com /nezhahq/nezha/security/advisories/GHSA-99gv-2m7h-3hh9
exploit, web, advisory
nvd.nist.gov /vuln/detail/CVE-2026-46716
advisory
github.com /nezhahq/nezha
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary