CVE-2026-55559

Published: Ago 28, 2026 Last Modified: Ago 29, 2026
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,8
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: high

Description

AI Translation Available

Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs inserts templateArgs from POST /api/instances and PATCH /api/instances/{instance} into YAML through VarStatement.append in yamcs-core/src/main/java/org/yamcs/templating/VarStatement.java without YAML-context escaping. The rendered configuration is parsed by YamcsServer.createInstance and loaded by YamcsServerInstance, allowing an attacker to inject a services entry for org.yamcs.ProcessRunner. Deployments without security.yaml expose the operation through the guest superuser, while secured deployments require SystemPrivilege.CreateInstances. Successful exploitation executes commands as the Yamcs service account. This issue is fixed in versions 5.12.8 and 5.13.2.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0055
Percentile
0,4th
Updated

Single Data Point

Only one EPSS measurement is available for this CVE. Trend analysis requires multiple data points over time.

94

Improper Control of Generation of Code ('Code Injection')

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control Integrity Confidentiality Availability Non-Repudiation
Potential Impacts:
Bypass Protection Mechanism Gain Privileges Or Assume Identity Execute Unauthorized Code Or Commands Hide Activities
Applicable Platforms
Languages: Interpreted
Technologies: AI/ML
Likelihood of Exploit: Medium
View CWE Details
470

Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Confidentiality Availability Other
Potential Impacts:
Execute Unauthorized Code Or Commands Alter Execution Logic Dos: Crash, Exit, Or Restart Other Read Application Data
Applicable Platforms
Languages: Java, PHP, Interpreted
View CWE Details
1336

Improper Neutralization of Special Elements Used in a Template Engine

Incomplete
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity
Potential Impacts:
Execute Unauthorized Code Or Commands
Applicable Platforms
Languages: Java, PHP, Python, JavaScript, Interpreted
Technologies: Not Technology-Specific, AI/ML, Client Server
View CWE Details
https://github.com/yamcs/yamcs/security/advisories/GHSA-73m…
https://github.com/yamcs/yamcs/security/advisories/GHSA-73mf-m39p-wpm9
https://github.com/yamcs/yamcs/commit/549f295cf8c5496a5e799…
https://github.com/yamcs/yamcs/commit/549f295cf8c5496a5e799d6bec2432ef976c82aa
https://github.com/yamcs/yamcs/commit/7192da1c49bdf5ab1d72e…
https://github.com/yamcs/yamcs/commit/7192da1c49bdf5ab1d72e579a47766a7c43e87c8
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.8
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.8
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.2
https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.2
https://github.com/yamcs/yamcs/security/advisories/GHSA-73m…
https://github.com/yamcs/yamcs/security/advisories/GHSA-73mf-m39p-wpm9