diff --git a/CHANGELOG.md b/CHANGELOG.md
index 38dda01e..3f1b620c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@ the frozen-backend fallback mirror it for their toolchains.
 ### Changed
 
 - Model Catalogue is one page: a setup summary (speech, transcription, dictation, language model) on top, one TTS / ASR / LLM switch, and each family's downloadable weights listed under its engines; the separate Models pane and the Settings → Voice → Engines / Models signposts are gone, the models directory and voice previews moved to Settings → Storage and the HF mirror to Network (#2013)
+- CosyVoice 3 installs patched protobuf and transformers releases, clearing five security advisories (#2030, #2031)
 
 ### CI
 
diff --git a/backend/engines/cosyvoice_subprocess/requirements.txt b/backend/engines/cosyvoice_subprocess/requirements.txt
index 6fafb8ad..bd3646f3 100644
--- a/backend/engines/cosyvoice_subprocess/requirements.txt
+++ b/backend/engines/cosyvoice_subprocess/requirements.txt
@@ -14,6 +14,8 @@
 #   affected release: diffusers, hydra-core, lightning, modelscope, onnx,
 #   protobuf and transformers. This exact set was installed on Windows and
 #   passes the installer's import probe (tests pin the advisory floors).
+#   transformers 5 was also checked against CosyVoice's own tokenizer (token
+#   ids identical to 4.57.6) and its cached step-by-step decoding.
 # - Dropped: deepspeed and tensorrt-cu12* (Linux-only acceleration);
 #   onnxruntime-gpu (the onnxruntime below serves every host); pyworld and
 #   pyarrow (not needed to import or run CosyVoice; pyworld has no Python 3.10
diff --git a/tests/test_cosyvoice_subprocess.py b/tests/test_cosyvoice_subprocess.py
index fa95fd0a..f933dd2c 100644
--- a/tests/test_cosyvoice_subprocess.py
+++ b/tests/test_cosyvoice_subprocess.py
@@ -233,16 +233,17 @@ def test_a_missing_model_override_is_an_error_not_a_silent_swap(monkeypatch, tmp
 
 
 # The first release of each package that fixes the advisories upstream's pins
-# fall under (OSV, checked 2026-09-10). Raising a pin is fine; going below
-# one of these reintroduces a known vulnerability.
+# fall under, per OSV and GitHub's advisory database (checked 2026-09-10;
+# only GitHub listed the protobuf and transformers ones). Raising a pin is
+# fine; going below one of these reintroduces a known vulnerability.
 _ADVISORY_FLOORS = {
     "diffusers": "0.38.0",
     "hydra-core": "1.3.4",
     "lightning": "2.6.6",
     "modelscope": "1.27.0",
     "onnx": "1.21.0",
-    "protobuf": "4.25.8",
-    "transformers": "4.53.0",
+    "protobuf": "5.29.6",
+    "transformers": "5.10.0",
 }