CVE-2026-54157: LobeHub: Unauthenticated SSRF in `/webapi/proxy`

Synopsis

A server-side request forgery (SSRF) vulnerability exists in the /webapi/proxy endpoint of LobeHub, an AI agent collaboration platform. The endpoint accepts a URL in a POST request body and fetches it server-side without requiring any authentication, making it reachable by any internet user. A successful attacker can issue arbitrary outbound HTTP requests from LobeHub's infrastructure, leak internal Vercel deployment metadata, and inject cookies into the lobehub.com domain via reflected Set-Cookie headers. No patched image rebuild is currently available on HarborGuard; the advisory is being tracked for upstream fix availability.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must reach the /webapi/proxy endpoint over the network; the service is exposed via HTTP to any internet-connected client.

• AuthenticationRequired

  Despite the CVE title describing the endpoint as unauthenticated, the CVSS vector records PR:H, meaning the scoring authority assessed that a highly privileged account is needed; reviewers should reconcile this against the prose description, which states no authentication is required.

• Victim interactionNot required

  No victim action is needed; the attacker sends a direct POST request to the endpoint without any user participation.

• Attack complexityDetail

  Attack complexity is Low, meaning the exploit is reliable and requires no special timing, race conditions, or environmental preconditions to succeed.

Blast Radius

• Reads internal Vercel deployment details, which may include environment variable names, internal hostnames, and deployment identifiers.
• Injects attacker-controlled cookies into the lobehub.com domain via reflected Set-Cookie headers, enabling session fixation or credential theft against lobehub.com users.
• Crashes or degrades services reachable from LobeHub's infrastructure by directing the proxy to issue high-volume or malformed requests to internal endpoints (Availability impact: High).
• Makes arbitrary outbound HTTP requests from LobeHub's server-side infrastructure, potentially reaching cloud metadata endpoints such as the AWS instance metadata service or equivalent Vercel runtime internals.