# [CRIT] [GHSA / CRITICAL] CVE-2026-46716: Nezha Monitoring: RoleMember can run shell on every server (cross-tenant RCE) via POST /api/v1/cron

**Source:** GitHub Security Advisories
**Published:** 2026-05-23
**Article:** https://github.com/advisories/GHSA-99gv-2m7h-3hh9

## Threat Profile

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

## Summary

`nezha`'s dashboard supports two user roles: `RoleAdmin` (Role==0) and `RoleMember` (Role==1). The cron routes `POST /api/v1/cron` and `PATCH /api/v1/cron/:id` are wired through `commonHandler` (any authenticated user) rather than `adminHandler`, and the per-server permission check on cron creation has a vacuous-true bypass.

A `RoleMember` user can create a scheduled cron task with `…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-46716`

## MITRE ATT&CK Techniques

- **T1190** — Exploit Public-Facing Application
- **T1528** — Steal Application Access Token
- **T1098.001** — Account Manipulation: Additional Cloud Credentials
- **T1053.005** — Scheduled Task
- **T1053.005** — Persistence (article-specific)
- **T1078** — Valid Accounts
- **T1068** — Exploitation for Privilege Escalation
- **T1059.004** — Command and Scripting Interpreter: Unix Shell
- **T1003.008** — OS Credential Dumping: /etc/passwd and /etc/shadow
- **T1552.005** — Unsecured Credentials: Cloud Instance Metadata API
- **T1057** — Process Discovery
- **T1071.001** — Application Layer Protocol: Web Protocols

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Nezha CVE-2026-46716 exploit: POST /api/v1/cron with empty servers + CronCoverAll

`UC_213_4` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=t count min(_time) as firstTime max(_time) as lastTime values(Web.url) as url values(Web.http_user_agent) as ua values(Web.status) as status values(Web.src) as src from datamodel=Web.Web where Web.http_method=POST AND Web.url="*/api/v1/cron*" AND NOT Web.url="*/api/v1/cron/*" by Web.dest Web.user Web.src Web.url
| `drop_dm_object_name(Web)`
| where status>=200 AND status<300
| join type=left src [search index=web sourcetype=*proxy* OR sourcetype=*waf* uri_path="/api/v1/cron" method=POST | rex field=_raw "\"servers\"\s*:\s*(?<servers>\[[^\]]*\])" | rex field=_raw "\"cover\"\s*:\s*(?<cover>\d+)" | where (servers="[]" AND cover="1") | table src cover servers]
| where isnotnull(cover) OR isnotnull(servers)
| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

### nezha-agent spawning credential-access shell commands on Linux (post-RCE)

`UC_213_5` · phase: **actions** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=t count min(_time) as firstTime max(_time) as lastTime values(Processes.process) as cmdline values(Processes.process_name) as proc_name values(Processes.parent_process) as parent_cmdline from datamodel=Endpoint.Processes where (Processes.parent_process_name="nezha-agent" OR Processes.parent_process="*/nezha-agent*" OR (Processes.parent_process_name IN ("sh","bash","dash","zsh") AND Processes.process_path="*/nezha-agent*")) AND (Processes.process="*/etc/shadow*" OR Processes.process="*169.254.169.254*" OR Processes.process="*iam/security-credentials*" OR Processes.process="*metadata.google.internal*" OR Processes.process="*metadata.azure.com*") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName has "nezha-agent"
   or InitiatingProcessParentFileName has "nezha-agent"
| where FileName in~ ("cat","less","more","head","tail","awk","sed","grep","curl","wget","sh","bash","dash","python","python3","perl")
| where ProcessCommandLine has_any (
    "/etc/shadow",
    "169.254.169.254",
    "iam/security-credentials",
    "metadata.google.internal",
    "metadata.azure.com",
    "/computeMetadata/v1",
    "/latest/meta-data"
  )
| project Timestamp, DeviceName, AccountName,
          ParentImage = InitiatingProcessFolderPath,
          ParentCmd   = InitiatingProcessCommandLine,
          GrandparentImage = InitiatingProcessParentFileName,
          ChildImage  = FolderPath,
          ChildCmd    = ProcessCommandLine,
          SHA256
| order by Timestamp desc
```

### nezha-agent outbound network connection to cloud instance-metadata service

`UC_213_6` · phase: **actions** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=t count min(_time) as firstTime max(_time) as lastTime values(All_Traffic.app) as app values(All_Traffic.user) as user from datamodel=Network_Traffic.All_Traffic where All_Traffic.dest="169.254.169.254" by All_Traffic.src All_Traffic.dest All_Traffic.dest_port All_Traffic.app
| `drop_dm_object_name(All_Traffic)`
| join type=inner src [| tstats summariesonly=t count from datamodel=Endpoint.Processes where (Processes.process_name="nezha-agent" OR Processes.parent_process_name="nezha-agent" OR Processes.parent_process="*nezha-agent*") by Processes.dest Processes.process Processes.process_name | rename Processes.dest as src Processes.process_name as proc_name Processes.process as proc_cmdline]
| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
// Two-stage: find IMDS connections, then filter to those whose initiating process chain includes nezha-agent
let ImdsHits = DeviceNetworkEvents
    | where Timestamp > ago(7d)
    | where RemoteIP == "169.254.169.254"
       or RemoteUrl has_any ("169.254.169.254", "metadata.google.internal", "metadata.azure.com")
    | project Timestamp, DeviceId, DeviceName, RemoteIP, RemoteUrl, RemotePort,
              InitiatingProcessId, InitiatingProcessFileName,
              InitiatingProcessParentFileName, InitiatingProcessCommandLine,
              InitiatingProcessAccountName;
ImdsHits
| where InitiatingProcessFileName has "nezha-agent"
   or InitiatingProcessParentFileName has "nezha-agent"
   or InitiatingProcessCommandLine has "nezha-agent"
// Catch grandparent chain via process-tree lookup
| union (
    ImdsHits
    | join kind=inner (
        DeviceProcessEvents
        | where Timestamp > ago(7d)
        | where InitiatingProcessFileName has "nezha-agent"
        | project DeviceId, ChildPid=ProcessId, ChildFile=FileName, ChildCmd=ProcessCommandLine, ChildTime=Timestamp
    ) on DeviceId
    | where InitiatingProcessId == ChildPid and Timestamp between (ChildTime .. ChildTime + 10m)
  )
| order by Timestamp desc
```

### OAuth consent / suspicious app grant

`UC_OAUTH_ABUSE` · phase: **actions** · confidence: **High**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Authentication.Authentication
    where Authentication.action="success"
      AND Authentication.signature IN (
        "Consent to application",
        "Add app role assignment grant to user",
        "Add OAuth2PermissionGrant",
        "Add delegated permission grant")
    by Authentication.user, Authentication.app, Authentication.src, Authentication.signature
| `drop_dm_object_name(Authentication)`
```

**Defender KQL:**
```kql
CloudAppEvents
| where Timestamp > ago(7d)
| where ActionType in ("Consent to application.","Add OAuth2PermissionGrant.","Add delegated permission grant.")
| project Timestamp, AccountObjectId, AccountDisplayName, ActivityType,
          ActivityObjects, IPAddress, UserAgent
```

### Scheduled task created with suspicious image / encoded args

`UC_SCHEDULED_TASK` · phase: **install** · confidence: **High**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Processes
    where Processes.process_name="schtasks.exe" AND Processes.process="*/create*"
      AND (Processes.process="*powershell*" OR Processes.process="*cmd.exe*"
        OR Processes.process="*rundll32*" OR Processes.process="*-enc*"
        OR Processes.process="*FromBase64*" OR Processes.process="*\Users\Public*"
        OR Processes.process="*\AppData\*")
    by Processes.dest, Processes.user, Processes.process, Processes.parent_process_name
| `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where FileName =~ "schtasks.exe"
| where ProcessCommandLine has "/create"
| where ProcessCommandLine has_any ("powershell","cmd.exe","rundll32","-enc","FromBase64","\Users\Public","\AppData\")
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName
```

### Article-specific behavioural hunt — [GHSA / CRITICAL] CVE-2026-46716: Nezha Monitoring: RoleMember can run shell on

`UC_213_3` · phase: **install** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-46716: Nezha Monitoring: RoleMember can run shell on ```
| tstats `summariesonly` count
    from datamodel=Endpoint.Filesystem
    where Filesystem.action IN ("created","modified")
      AND (Filesystem.file_path="*/etc/shadow*")
    by Filesystem.dest, Filesystem.user, Filesystem.process_name,
       Filesystem.file_path, Filesystem.file_name
| `drop_dm_object_name(Filesystem)`
```

**Defender KQL:**
```kql
// Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-46716: Nezha Monitoring: RoleMember can run shell on
// Hunts the actual binaries / paths / commandline fragments named
// in the article instead of a generic technique-class template.

// File-creation events for the named binaries / paths
DeviceFileEvents
| where Timestamp > ago(30d)
| where ActionType in ("FileCreated","FileModified")
| where (FolderPath has_any ("/etc/shadow"))
| project Timestamp, DeviceName, AccountName, FolderPath,
          FileName, ActionType, InitiatingProcessFileName,
          InitiatingProcessCommandLine
| order by Timestamp desc
```

### IOC-driven hunts (use shared templates)

These are standard IOC-substitution hunts — the canonical SPL and KQL live once in [`_TEMPLATES.md`](../_TEMPLATES.md), so we don't repeat the same boilerplate on every CVE / hash / network-IOC briefing.

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2026-46716`


## Why this matters

Severity classified as **CRIT** based on: CVE present, 7 use case(s) fired, 12 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.