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🛡️ CVE-2026-42088 — cosmos

🔴 CVSS 9.6 — Critical ⚠️ Exploit Public CWE-250 NVD
9.6
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

OpenC3 COSMOS: Permissions Bypass Provides User Access to Unassigned Administrative Actions via Script Runner Tool

**Vulnerability Type: Execution with Unnecessary Privileges

Attack type: Authenticated remote

Impact: Data disclosure/manipulation, privilege escalation

Affected components: The following docker images:

• Openc3inc/openc3-COSMOS-script-runner-api**

The Script Runner widget allows users to execute Python and Ruby scripts directly from the openc3-COSMOS-script-runner-api container. Because all the docker containers share a network, users can execute specially crafted scripts to bypass the API permissions check and perform administrative actions, including reading and modifying data inside the Redis database, which can be used to read secrets and change COSMOS settings, as well as read and write to the buckets service, which holds configuration, log, and plugin files. These actions are normally only available from the Admin Console or with administrative privileges. Any user with permission to create and run scripts can connect to any service in the docker network.

<img width="940" height="473" alt="image" src="https://github.com/user-attachments/assets/bf524163-127d-4349-999b-cefc53d4374d" />

Figure 1: Environment variables, including Redis credentials, found in the Script Runner container

A Ruby script is used to expose the Redis username, password, hostname, and port. These credentials might also be found from the source code or through a brute-force attack.

<img width="940" height="507" alt="image" src="https://github.com/user-attachments/assets/6d3ccad4-949d-4eeb-a5f8-3aca48bbe815" />

Figure 2: A Python script is used to add data to Redis and retrieve the new data

A Python script is then used to create a new entry in the Redis database called openc3__settings_hacked with a key of store_url and a value of http://hacked.com.

<img width="940" height="70" alt="image" src="https://github.com/user-attachments/assets/fcef13be-5416-4627-9c95-617a24674ee0" />

Figure 3: The new data found in the Redis database

The new entry was successfully added to the Redis database, as is confirmed by using redis-cli.

The following example shows how an attacker might change the plugin store URL file that is stored in the config bucket.

<img width="940" height="640" alt="image" src="https://github.com/user-attachments/assets/681b4dd6-4b6e-4a91-8480-0c9fbff76ede" />

Figure 4: Uploading file to change the plugin store URL setting

<img width="940" height="189" alt="image" src="https://github.com/user-attachments/assets/630db0bb-217e-4205-be1d-e9891516b22f" />

Figure 5: The URL file was successfully changed

Steps To Reproduce

1. Run the following Ruby code to find the Redis credentials:

```ruby

puts env | grep redis

```

3. Add the following Python script with the credentials to create a new entry and read it

```python

import redis

import json

import time

r = redis.Redis(

host = 'openc3-redis',

port = 6379,

username = 'openc3',

password = 'openc3password',

decode_responses=True

)

# Save a setting

setting_data = {

'name': 'store_url',

'data': 'http://hacked.com',

'updated_at': time.time_ns()

}

r.hset('openc3__settings_hacked','store_url',json.dumps(setting_data))

print(r.hget('openc3__settings_hacked','store_url'))

```

Recommendations

• Limit the permissions of the script runner API to prevent lower level users from performing administrative actions

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2026-42088 is classified as CWE-250: Execution with Unnecessary Privileges. The software runs with more privilege than the task needs, so any flaw in it inherits that privilege.

Affected software

CVE-2026-42088 is recorded against 2 packages.

  • cosmos
  • openc3 (fixed in 7.0.0)

Timeline and source

Published on 4 May 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

github.com
github.com
github.com
github.com

Other advisories for this package

cosmos has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-250: Execution with Unnecessary Privileges) in other software:

Details

Severity CRITICAL
CVSS Score 9.6
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
CWE CWE-250
Public Exploit ⚠️ Yes
Source NVD
Published 2026-05-04
Updated 2026-08-20
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
cosmos
openc3 7.0.0

Similar Threats

Exploit Protection

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