diff --git a/Sources/App/Core/ErrorMiddleware.swift b/Sources/App/Core/ErrorMiddleware.swift
index f78dc68c1..a89b1665d 100644
--- a/Sources/App/Core/ErrorMiddleware.swift
+++ b/Sources/App/Core/ErrorMiddleware.swift
@@ -25,9 +25,14 @@ final class ErrorMiddleware: AsyncMiddleware {
     func respond(to req: Request, chainingTo next: AsyncResponder) async throws -> Response {
         do {
             return try await next.respond(to: req)
-        } catch let error as AbortError where error.status.code >= 400 {
-            let statusCode = error.status.code
-            let isCritical = (statusCode >= 500)
+        } catch let error as AbortError where error.status.code < 400 {
+            throw error
+        } catch {
+            // Errors that aren't `AbortError`s would otherwise escape this middleware and be
+            // turned into an unlogged, raw 500 by Vapor's default error handling.
+            // See https://github.com/SwiftPackageIndex/SwiftPackageIndex-Server/issues/3944
+            let abortError = error as? AbortError ?? Abort(.internalServerError)
+            let isCritical = (abortError.status.code >= 500)
 
             @Dependency(\.logger) var logger
 
@@ -37,9 +42,9 @@ final class ErrorMiddleware: AsyncMiddleware {
                 logger.error("\(error): \(req.url)")
             }
 
-            return ErrorPage.View(path: req.url.path, error: error)
+            return ErrorPage.View(path: req.url.path, error: abortError)
                 .document()
-                .encodeResponse(status: error.status)
+                .encodeResponse(status: abortError.status)
         }
     }
 
diff --git a/Tests/AppTests/ErrorMiddlewareTests.swift b/Tests/AppTests/ErrorMiddlewareTests.swift
index d13c2b2e1..338b015c1 100644
--- a/Tests/AppTests/ErrorMiddlewareTests.swift
+++ b/Tests/AppTests/ErrorMiddlewareTests.swift
@@ -26,8 +26,11 @@ extension AllTests.ErrorMiddlewareTests {
         app.get("ok") { _ in return "ok" }
         app.get("404") { req async throws -> Response in throw Abort(.notFound) }
         app.get("500") { req async throws -> Response in throw Abort(.internalServerError) }
+        app.get("unknown-error") { req async throws -> Response in throw TestError() }
     }
 
+    struct TestError: Error { }
+
     @Test func custom_routes() async throws {
         try await withSPIApp(setup) { app in
             // Test to ensure the test routes we've set up in setUpWithError are in effect
@@ -72,4 +75,20 @@ extension AllTests.ErrorMiddlewareTests {
         }
     }
 
+    @Test func non_abort_error() async throws {
+        // Ensure errors that aren't AbortErrors are also converted to html error pages
+        // https://github.com/SwiftPackageIndex/SwiftPackageIndex-Server/issues/3944
+        try await withDependencies {
+            $0.environment.dbId = { nil }
+        } operation: {
+            try await withSPIApp(setup) { app in
+                try await app.testing().test(.GET, "unknown-error", afterResponse: { response async in
+                    #expect(response.status == .internalServerError)
+                    #expect(response.content.contentType == .html)
+                    #expect(response.body.asString().contains("500 - Internal Server Error"))
+                })
+            }
+        }
+    }
+
 }