SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-77602

From 5.1.0 until 7.3.0, authenticated non-administrator users can write content under targets_modified/ that is later executed by multiple configuration paths below the intended code-execution privilege tier.

CRITICAL 9.9EPSS 0.72%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.72%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.1.0 until 7.3.0, authenticated non-administrator users can write content under targets_modified/ that is later executed by multiple configuration paths below the intended code-execution privilege tier. Table and command or telemetry definitions are processed through ConfigParser, PacketConfig, GENERIC_READ_CONVERSION, or GENERIC_WRITE_CONVERSION, allowing ERB rendering or Ruby and Python evaluation, while openc3-cosmos-script-runner-api/scripts/run_suite_analysis.rb executes suite procedure files through require. Storage uploads, screen saves, and script creation can place content in the overlay, and triggering table processing, a cmd/tlm reload, or suite analysis executes the content in cmd-tlm-api, decom microservices, or Script Runner with access to internal credentials and data. This issue is fixed in version 7.3.0.

CVSS 3.1
9.9 CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS
0.72% probability · 54th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-94
Source
security-advisories@github.com
EPSS trend
0%3%5%24 September 2026: 0.57%26 October 2026: 0.72%24 September 202626 October 2026

EPSS moved from 0.6% on 24 September 2026 to 0.7% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.