From bd5b2847ec332a478e012b630f26751f65509de9 Mon Sep 17 00:00:00 2001
From: Abdullah Alqahtani <61029571+anqorithm@users.noreply.github.com>
Date: Tue, 3 Nov 2026 01:30:39 +0100
Subject: [PATCH] fix(cache): enforce string item limits in bytes

---
 litellm/caching/in_memory_cache.py         |  2 +-
 tests/unit/caching/test_in_memory_cache.py | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/litellm/caching/in_memory_cache.py b/litellm/caching/in_memory_cache.py
index 6b40c48c4ef..fe07268bc91 100644
--- a/litellm/caching/in_memory_cache.py
+++ b/litellm/caching/in_memory_cache.py
@@ -62,7 +62,7 @@ class InMemoryCache(BaseCache):
         try:
             # Fast path for common primitive types that are typically small
             if (
-                isinstance(value, (bool, int, float, str))
+                isinstance(value, (bool, int, float))
                 and len(str(value)) < self.max_size_per_item * MAX_SIZE_PER_ITEM_IN_MEMORY_CACHE_IN_KB
             ):  # Conservative estimate
                 return True
diff --git a/tests/unit/caching/test_in_memory_cache.py b/tests/unit/caching/test_in_memory_cache.py
index 901832937b5..38fb7ac467b 100644
--- a/tests/unit/caching/test_in_memory_cache.py
+++ b/tests/unit/caching/test_in_memory_cache.py
@@ -392,3 +392,14 @@ async def test_async_increment_pipeline_keeps_each_key_for_its_own_ttl() -> None
 
     assert cache.get_cache("minute") is None
     assert cache.get_cache("day") == 1
+
+
+@pytest.mark.parametrize("character", ("Ā", "界", "😀"))
+def test_cache_rejects_unicode_strings_exceeding_the_byte_limit(character: str) -> None:
+    cache: Final = InMemoryCache(max_size_per_item=1, clock=lambda: 100.0)
+    oversized: Final = character * 700
+    assert sys.getsizeof(oversized) > 1024
+    cache.set_cache("large", oversized)
+    assert cache.get_cache("large") is None
+    cache.set_cache("small", character * 10)
+    assert cache.get_cache("small") == character * 10