diff --git a/lib/std/crypto/aes_siv.zig b/lib/std/crypto/aes_siv.zig
index 4cbbca2eeb61a7d6ff449716533be34d1d0b6be1..b3be102831e902f61864a67ca304b01dfa73c32a 100644
--- a/lib/std/crypto/aes_siv.zig
+++ b/lib/std/crypto/aes_siv.zig
@@ -226,9 +226,10 @@ fn AesSiv(comptime Aes: anytype) type {
 
         /// Encrypts plaintext with multiple associated data components.
         /// This is the most general form of AES-SIV encryption that accepts
-        /// an arbitrary vector of associated data strings as specified in RFC 5297.
+        /// a vector of up to 126 associated data strings as specified in RFC 5297.
         pub fn encryptWithAdVector(c: []u8, tag: *[tag_length]u8, m: []const u8, ad: []const []const u8, key: [key_length]u8) void {
             debug.assert(c.len == m.len);
+            debug.assert(ad.len <= 126); // AES-SIV supports at most 126 associated data components
 
             // Split key into K1 (for S2V) and K2 (for CTR)
             const k1 = key[0 .. Aes.key_bits / 8];
@@ -260,9 +261,10 @@ fn AesSiv(comptime Aes: anytype) type {
 
         /// Decrypts ciphertext with multiple associated data components.
         /// This is the most general form of AES-SIV decryption that accepts
-        /// an arbitrary vector of associated data strings as specified in RFC 5297.
+        /// a vector of up to 126 associated data strings as specified in RFC 5297.
         pub fn decryptWithAdVector(m: []u8, c: []const u8, tag: [tag_length]u8, ad: []const []const u8, key: [key_length]u8) AuthenticationError!void {
             assert(c.len == m.len);
+            assert(ad.len <= 126); // AES-SIV supports at most 126 associated data components
 
             // Split key into K1 (for S2V) and K2 (for CTR)
             const k1 = key[0 .. Aes.key_bits / 8];