diff --git a/packages/app/src/app/api/v1/benchmarks/route.ts b/packages/app/src/app/api/v1/benchmarks/route.ts
index c79f1aa74..9e9641820 100644
--- a/packages/app/src/app/api/v1/benchmarks/route.ts
+++ b/packages/app/src/app/api/v1/benchmarks/route.ts
@@ -20,10 +20,16 @@ const getCachedBenchmarks = cachedQuery(
   { blobOnly: true },
 );
 
+const ISO_DATE_RE = /^\d{4}-\d{2}-\d{2}$/u;
+
 export async function GET(request: NextRequest) {
   const params = request.nextUrl.searchParams;
   const model = params.get('model') ?? '';
-  const date = params.get('date') ?? undefined;
+  // Reject anything that isn't an ISO YYYY-MM-DD — otherwise postgres-js will
+  // coerce `${date}::date` via `new Date(date)`, which on garbage produces NaN
+  // and throws `Invalid time value` from toISOString → opaque 500.
+  const rawDate = params.get('date');
+  const date = rawDate && ISO_DATE_RE.test(rawDate) ? rawDate : undefined;
   const exact = params.get('exact') === 'true';
   const dbModelKeys = DISPLAY_MODEL_TO_DB[model];
   if (!dbModelKeys || dbModelKeys.length === 0) {
diff --git a/packages/app/src/hooks/api/use-benchmarks.ts b/packages/app/src/hooks/api/use-benchmarks.ts
index 6da1568e3..2087c27db 100644
--- a/packages/app/src/hooks/api/use-benchmarks.ts
+++ b/packages/app/src/hooks/api/use-benchmarks.ts
@@ -9,9 +9,15 @@ export function benchmarkQueryOptions(
   enabled = true,
   exact?: boolean,
 ) {
+  // 'latest' is only a queryKey marker meaning "no specific date" — must NOT
+  // be sent to the API as a date filter (postgres-js coerces `${date}::date`
+  // params via `new Date(date)`, which on 'latest' produces NaN and throws
+  // `Invalid time value` from toISOString → 500 to the client).
+  const dateForFetch = date === 'latest' ? undefined : date;
   return {
     queryKey: ['benchmarks', model, date, exact ? 'exact' : 'latest'] as const,
-    queryFn: ({ signal }: { signal: AbortSignal }) => fetchBenchmarks(model, date, exact, signal),
+    queryFn: ({ signal }: { signal: AbortSignal }) =>
+      fetchBenchmarks(model, dateForFetch, exact, signal),
     enabled: enabled && Boolean(model),
   };
 }