diff --git a/service_vm/comm/src/message.rs b/service_vm/comm/src/message.rs
index 570cf38..2671f7d 100644
--- a/service_vm/comm/src/message.rs
+++ b/service_vm/comm/src/message.rs
@@ -99,6 +99,9 @@
     /// An error happened during the interaction with coset.
     CosetError,
 
+    /// An unexpected internal error occurred.
+    InternalError,
+
     /// Any key to sign lacks a valid MAC. Maps to `STATUS_INVALID_MAC`.
     InvalidMac,
 
@@ -116,6 +119,7 @@
                 write!(f, "Failed to invoke a BoringSSL API: {api_name:?}")
             }
             Self::CosetError => write!(f, "Encountered an error with coset"),
+            Self::InternalError => write!(f, "An unexpected internal error occurred"),
             Self::InvalidMac => write!(f, "A key to sign lacks a valid MAC."),
             Self::KeyToSignHasEmptyPayload => write!(f, "No payload found in a key to sign."),
             Self::CborValueError => {