CVE-2026-46580: eclipse foundation eclipse theia

Vulnerability summary

CVE-2026-46580 is a high (CVSS 8.8) vulnerability in eclipse foundation eclipse theia. EPSS estimates a 0.51% chance of exploitation in the next 30 days, higher than 42% of scored vulnerabilities.

Timeline

1. 18-06-2026
   PublishedVulnerability first disclosed.
2. 19-06-2026
   Last modifiedVulnerability information updated.

Description

In Eclipse Theia versions prior to 1.71.0, files matching the pattern .prompts/*.prompttemplate in a workspace were automatically loaded and could override or extend the AI agent's system prompts. An attacker could craft a malicious repository containing prompt template files that, when the workspace was opened in Theia, replaced the AI's system instructions with attacker-controlled content (indirect prompt injection). Combined with other AI chat features available in untrusted workspaces, this enabled attack chains leading to data exfiltration via Markdown image rendering or arbitrary command execution via task definitions.

• CWE-1427Improper Neutralization of Input Used for LLM PromptingThe product uses externally-provided data to build prompts provided to large language models (LLMs), but the way these prompts are constructed causes the LLM to fail to distinguish between user-supplied inputs and developer provided system directives.
• CWE-829Inclusion of Functionality from Untrusted Control SphereThe product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.