CVE-2026-108716

Description

mcp-remote 0.8.0 through 0.14.3 contains a cleartext transmission vulnerability in authorizeWithDeviceCode that sends client secrets and receives tokens without enforcing HTTPS endpoints. When discovered device authorization and token endpoints are non-loopback http URLs, on-path network attackers can capture the client secret plus issued access and refresh tokens.

References

• https://github.com/punkpeye/mcp-remote
• https://github.com/punkpeye/mcp-remote/blob/v0.14.3/src/lib/client-credentials.ts#L37-L47
• https://github.com/punkpeye/mcp-remote/blob/v0.14.3/src/lib/device-authorization.ts#L64-L170
• https://hackmd.io/@haind03/punkpeye-mcp-remote-device-code-cleartext-oauth-transport
• https://www.vulncheck.com/advisories/mcp-remote-0.8.0-through-0.14.3-cleartext-credential-transmission-via-device-code-oauth-grant