Spinnaker’s Echo component parses Spring Expression Language (SpEL) expressions that relate to expected artifacts. In versions older than 2026.1.0, 2026.0.1, 2025.4.2, and 2025.3.2, the SpEL context was not limited to a whitelist of trusted classes, giving an attacker full access to the Java Virtual Machine. This flaw can allow arbitrary Java class loading and execution, including running system commands, reading or writing files, and other actions that compromise confidentiality, integrity, and availability. The vulnerability corresponds to CWE-94, an injection flaw that enables code execution.

The affected product is Spinnaker, an open‑source, multi‑cloud continuous delivery platform. Versions before 2026.1.0, 2026.0.1, 2025.4.2, and 2025.3.2 are vulnerable. Patches are included in releases 2026.1.0, 2026.0.1, 2025.4.2, and 2025.3.2. Earlier releases do not contain the fix.

The CVSS score is 10, indicating a severe risk. The EPSS score is not available, so the likelihood of exploitation cannot be quantified from the available data. The vulnerability is not listed in the CISA KEV catalog. Perhaps the most likely attack vector is an authenticated user who crafts malicious SpEL expressions within artifact configurations; a pass‑the‑hash or privilege escalation scenario could also be feasible because the untrusted context allows arbitrary JVM access. If an attacker can supply these expressions, they can execute arbitrary code on the Spinnaker host.