diff --git a/CMakeLists.txt b/CMakeLists.txt
index 502056f221..a7ac639075 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -132,6 +132,9 @@ set(CMAKE_DISABLE_FIND_PACKAGE_OpenSSL On)
 # many tests require handling of signals themselves and even when they don't we'd like for them to generate a core dump, this
 # is effectively --catch_system_errors=no broadly across all tests
 add_compile_definitions(BOOST_TEST_DEFAULTS_TO_CORE_DUMP)
+# softfloat's legacy float32_t/float64_t aliases collide with arm_neon.h, which Boost.Unordered pulls in on arm64;
+# nothing here uses them.
+add_compile_definitions(SOFTFLOAT_DISABLE_LEGACY_TYPE_ALIASES)
 
 add_definitions(-DSYSIO_SYS_VM_RUNTIME_ENABLED)
 
diff --git a/cmake/SysioTester.cmake.in b/cmake/SysioTester.cmake.in
index 526fc41ca2..d260495939 100644
--- a/cmake/SysioTester.cmake.in
+++ b/cmake/SysioTester.cmake.in
@@ -311,6 +311,13 @@ target_include_directories(SysioChain INTERFACE
         @CMAKE_INSTALL_FULL_INCLUDEDIR@/wasm-jit
         @CMAKE_INSTALL_FULL_INCLUDEDIR@/softfloat)
 
+# softfloat is linked above as a raw archive, so the definitions its CMake package carries are repeated:
+# THREAD_LOCAL is the storage class the archive's per-thread state was built with, and the alias disable
+# keeps softfloat's legacy float32_t/float64_t typedefs away from arm_neon.h on arm64.
+target_compile_definitions(SysioChain INTERFACE
+        THREAD_LOCAL=__thread
+        SOFTFLOAT_DISABLE_LEGACY_TYPE_ALIASES)
+
 add_library(SysioTester INTERFACE)
 
 target_link_libraries(SysioTester INTERFACE
diff --git a/unittests/softfloat_thread_local_tests.cpp b/unittests/softfloat_thread_local_tests.cpp
new file mode 100644
index 0000000000..906486d2fc
--- /dev/null
+++ b/unittests/softfloat_thread_local_tests.cpp
@@ -0,0 +1,62 @@
+/**
+ * Berkeley SoftFloat keeps the rounding mode and exception flags in per-thread state (softfloat 3.0.0#3): a
+ * worker thread starts from the defaults and leaks nothing back to the thread that spawned it. With the
+ * process-global state of 3.0.0#2 every check below fails.
+ */
+extern "C" {
+#include <softfloat/softfloat.h>
+}
+#include <softfloat/softfloat.hpp>
+
+#include <boost/test/unit_test.hpp>
+
+#include <cstdint>
+#include <thread>
+
+namespace {
+
+const softfloat32_t one = {0x3f800000u};
+const softfloat32_t zero = {0u};
+const softfloat32_t minus_one = {0xbf800000u};
+
+/// Other suites may leave the calling thread's state behind; start from the defaults and put them back.
+struct softfloat_state_guard {
+   softfloat_state_guard() { reset(); }
+   ~softfloat_state_guard() { reset(); }
+   static void reset() {
+      softfloat_roundingMode = softfloat_round_near_even;
+      softfloat_exceptionFlags = 0;
+   }
+};
+
+} // namespace
+
+BOOST_AUTO_TEST_SUITE(softfloat_thread_local_tests)
+
+BOOST_AUTO_TEST_CASE(rounding_mode_and_exception_flags_are_per_thread) {
+   softfloat_state_guard guard;
+
+   softfloat_roundingMode = softfloat_round_max;
+   f32_div(one, zero);
+   BOOST_CHECK_EQUAL(unsigned(softfloat_exceptionFlags), unsigned(softfloat_flag_infinite));
+
+   unsigned worker_mode = ~0u;
+   unsigned worker_flags_before = ~0u;
+   unsigned worker_flags_after = 0;
+   std::thread worker([&] {
+      worker_mode = softfloat_roundingMode;
+      worker_flags_before = softfloat_exceptionFlags;
+      softfloat_roundingMode = softfloat_round_minMag;
+      f32_sqrt(minus_one);
+      worker_flags_after = softfloat_exceptionFlags;
+   });
+   worker.join();
+
+   BOOST_CHECK_EQUAL(worker_mode, unsigned(softfloat_round_near_even));
+   BOOST_CHECK_EQUAL(worker_flags_before, 0u);
+   BOOST_CHECK_EQUAL(worker_flags_after, unsigned(softfloat_flag_invalid));
+   BOOST_CHECK_EQUAL(unsigned(softfloat_roundingMode), unsigned(softfloat_round_max));
+   BOOST_CHECK_EQUAL(unsigned(softfloat_exceptionFlags), unsigned(softfloat_flag_infinite));
+}
+
+BOOST_AUTO_TEST_SUITE_END()
diff --git a/vcpkg-configuration.json b/vcpkg-configuration.json
index 1f50d78f23..b0062a485d 100644
--- a/vcpkg-configuration.json
+++ b/vcpkg-configuration.json
@@ -10,8 +10,8 @@
     {
       "kind": "git",
       "repository": "https://github.com/wire-network/wire-vcpkg-registry",
-      "baseline": "2806c1bc39dda520c100b5ea75aef8aa2693a85f",
-      "reference": "2806c1bc39dda520c100b5ea75aef8aa2693a85f",
+      "baseline": "abed0cc16f9e9514fec4a0b6751bc34ec427ca0d",
+      "reference": "abed0cc16f9e9514fec4a0b6751bc34ec427ca0d",
       "packages": [
         "boost",
         "softfloat",
diff --git a/vcpkg.json b/vcpkg.json
index 6ab201bad6..c595a60419 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -147,7 +147,7 @@
     },
     {
       "name": "softfloat",
-      "version": "3.0.0#2"
+      "version": "3.0.0#3"
     },
     {
       "name": "wire-sys-vm",