Know every vulnerabilitybefore it knows you.
DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.
GHSA-jrrm-9hc7-2v3h
omnigentSummary
An authenticated user with edit access to their own session can overwrite a shared/template agent by uploading a full agent bundle through PUT /sessions/{session_id}/agent.
Shared/template agents are shown as not MCP-editable, but this upload path still accepts a replacement bundle. By adding a stdio MCP server to the shared agent, the attacker can cause future runner sessions using that shared agent to start an attacker-controlled command.
Details
The vulnerable endpoint is the full agent bundle upload route: PUT /sessions/{session_id}/agent
This route checks whether the caller can edit the session: LEVEL_EDIT session permission check
But it does not check whether the bound agent is a shared/template agent.
Shared/template agents have:
agent.session_id is None
The API already exposes that these agents are not meant to be MCP-editable: mcp_servers_editable is false for shared/template agents
The direct MCP edit endpoint correctly blocks shared/template agents: session_mcp_servers.py shared-agent guard
if agent.session_id is None:
raise OmnigentError("Built-in agents are read-only through this endpoint.")
The full bundle upload endpoint is missing that same guard. It stores the uploaded bundle and updates the agent row: agent_store.update(agent.id, new_loc)
For shared/template agents, this changes the shared agent itself, not only the attacker's session.
This becomes command execution because stdio MCP servers start the configured command as a runner subprocess: tools/mcp.py stdio subprocess launch
Suggested fix: add the same agent.session_id is None guard to PUT /sessions/{session_id}/agent.
Impact
This is authenticated RCE against Omnigent runner hosts. A normal authenticated user with edit access to their own session can poison a shared/template agent bundle, even though that agent is shown as not MCP-editable. The poisoned bundle can then be used by future sessions created from the same shared agent.
Because stdio MCP servers run as local subprocesses, the attacker-controlled command executes with the permissions of the Omnigent runner process. In a shared or company-hosted deployment, this can let an attacker read runner-accessible files and credentials, modify workspace data, disrupt runner availability, pivot to internal services reachable from the runner, or establish an interactive remote shell if outbound networking is allowed.
This is high impact because it turns normal shared-agent session access into command execution on runner infrastructure used by other sessions.
Upload your own SBOM in CycloneDX 1.6 or higher (JSON) directly here to check your vulnerabilities.
Drag and drop some file here, or click to select
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
Browse More
Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.
Checkout DevGuard