SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-46621

Prior to 5.12.7, the Yamcs script evaluation engine for Python algorithms dynamically compiled and evaluated user-controlled algorithm text using Jython through the JSR-223 ScriptEngine API without enforcing a secure sandbox, so an authenticated user…

CRITICAL 9.1EPSS 1.12%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.12%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Yamcs is a mission control framework. Prior to 5.12.7, the Yamcs script evaluation engine for Python algorithms dynamically compiled and evaluated user-controlled algorithm text using Jython through the JSR-223 ScriptEngine API without enforcing a secure sandbox, so an authenticated user with the ChangeMissionDatabase privilege could override an existing Python algorithm's logic through the mission database REST API and import and execute arbitrary Java classes such as java.lang.Runtime to achieve remote code execution on the underlying host operating system. This issue is fixed in versions 5.12.7 and 5.13.0, which disable algorithm editing by default.

CVSS 3.1
9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
EPSS
1.12% probability · 66th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-94
Affected
spaceapplications/yamcs
Source
security-advisories@github.com
EPSS trend
0%3%5%26 October 2026: 1.12%26 October 202626 October 2026

EPSS 1.1% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

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