diff --git a/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.cpp b/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.cpp
index 0e08a76d9d..9ee6622009 100644
--- a/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.cpp
+++ b/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.cpp
@@ -156,6 +156,13 @@ size_t UnsignedBigInteger::trimmed_length() const
     return m_cached_trimmed_length.value();
 }
 
+void UnsignedBigInteger::clamp_to_trimmed_length()
+{
+    auto length = trimmed_length();
+    if (m_words.size() > length)
+        m_words.resize(length);
+}
+
 FLATTEN UnsignedBigInteger UnsignedBigInteger::plus(const UnsignedBigInteger& other) const
 {
     UnsignedBigInteger result;
@@ -578,7 +585,7 @@ FLATTEN void UnsignedBigInteger::shift_left_without_allocation(
 
         // output += (carry_word << temp_result.length())
         // FIXME : Using temp_plus this way to transform carry_word into a bigint is not
-        // efficient nor pretty. Maybe we should have an "add_with_shift" method ?
+        //         efficient nor pretty. Maybe we should have an "add_with_shift" method ?
         temp_plus.set_to_0();
         temp_plus.m_words.append(carry_word);
         shift_left_by_n_words(temp_plus, temp_result.length(), temp_result);
diff --git a/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.h b/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.h
index 51c1d9f776..b2805e685c 100644
--- a/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.h
+++ b/Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.h
@@ -81,6 +81,8 @@ public:
     // The "trimmed length" is the number of words after trimming leading zeroed words
     size_t trimmed_length() const;
 
+    void clamp_to_trimmed_length();
+
     UnsignedBigInteger plus(const UnsignedBigInteger& other) const;
     UnsignedBigInteger minus(const UnsignedBigInteger& other) const;
     UnsignedBigInteger bitwise_or(const UnsignedBigInteger& other) const;
diff --git a/Userland/Libraries/LibCrypto/NumberTheory/ModularFunctions.cpp b/Userland/Libraries/LibCrypto/NumberTheory/ModularFunctions.cpp
index 4125916a84..990f2c4323 100644
--- a/Userland/Libraries/LibCrypto/NumberTheory/ModularFunctions.cpp
+++ b/Userland/Libraries/LibCrypto/NumberTheory/ModularFunctions.cpp
@@ -150,6 +150,13 @@ UnsignedBigInteger ModularPower(const UnsignedBigInteger& b, const UnsignedBigIn
         UnsignedBigInteger::multiply_without_allocation(base, base, temp_1, temp_2, temp_3, temp_4, temp_multiply);
         UnsignedBigInteger::divide_without_allocation(temp_multiply, m, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder);
         base.set_to(temp_remainder);
+
+        // Note that not clamping here would cause future calculations (multiply, specifically) to allocate even more unused space
+        // which would then persist through the temp bigints, and significantly slow down later loops.
+        // To avoid that, we can clamp to a specific max size, or just clamp to the min needed amount of space.
+        ep.clamp_to_trimmed_length();
+        exp.clamp_to_trimmed_length();
+        base.clamp_to_trimmed_length();
     }
     return exp;
 }