diff --git a/Zend/zend_float.h b/Zend/zend_float.h
index 12aa02005c2a..133f58460c33 100644
--- a/Zend/zend_float.h
+++ b/Zend/zend_float.h
@@ -20,6 +20,8 @@
 
 #include "zend_portability.h"
 
+#include <math.h>
+
 BEGIN_EXTERN_C()
 
 /*
@@ -413,4 +415,21 @@ END_EXTERN_C()
 
 #endif /* FPU CONTROL */
 
+/* zend_init_fpu() clamps the x87 FPU to double precision (53-bit mantissa) for
+ * the whole request. libm's sinh() computes on the x87 unit and relies on the
+ * extended range to round correctly to double, so while that clamp is in place
+ * its result is off by one or more ULP. Restore extended precision for the call
+ * and truncate the result back to double. Compiles down to a plain sinh()
+ * everywhere XPFPA_HAVE_CW is 0, which includes x86-64 and arm64. */
+static zend_always_inline double zend_sinh(double num)
+{
+#if XPFPA_HAVE_CW
+	XPFPA_DECLARE
+	XPFPA_SWITCH_DOUBLE_EXTENDED();
+	XPFPA_RETURN_DOUBLE(sinh(num));
+#else
+	return sinh(num);
+#endif
+}
+
 #endif
diff --git a/ext/standard/math.c b/ext/standard/math.c
index e13f153f63e2..3e4f3678775d 100644
--- a/ext/standard/math.c
+++ b/ext/standard/math.c
@@ -535,7 +535,7 @@ PHP_FUNCTION(sinh)
 	ZEND_PARSE_PARAMETERS_START(1, 1)
 		Z_PARAM_DOUBLE(num)
 	ZEND_PARSE_PARAMETERS_END();
-	RETURN_DOUBLE(sinh(num));
+	RETURN_DOUBLE(zend_sinh(num));
 }
 /* }}} */
 
diff --git a/ext/standard/tests/math/sinh_fpu_precision.phpt b/ext/standard/tests/math/sinh_fpu_precision.phpt
new file mode 100644
index 000000000000..a646d388474d
--- /dev/null
+++ b/ext/standard/tests/math/sinh_fpu_precision.phpt
@@ -0,0 +1,48 @@
+--TEST--
+sinh(): results must not lose precision when the FPU is clamped to double precision
+--INI--
+serialize_precision=-1
+--FILE--
+<?php
+/* On i386 the x87 FPU is the platform default and zend_init_fpu() clamps it to
+ * double precision (53-bit mantissa) for the whole request. libm's sinh()
+ * computes on the x87 unit and relies on the extended range to round correctly
+ * to double, so while that clamp is in place its result is off by one or more
+ * ULP.
+ *
+ * Every expected value below is the correctly rounded double, verified against
+ * a high-precision reference and written as the shortest decimal that
+ * round-trips back to it. All arguments are exact binary fractions. */
+
+echo "-- reference points already correct on every platform --\n";
+var_dump(sinh(0));
+var_dump(sinh(1));
+var_dump(sinh(17));
+echo "-- inputs the FPU clamp gets wrong --\n";
+var_dump(sinh(3));
+var_dump(sinh(5));
+var_dump(sinh(6));
+var_dump(sinh(7));
+var_dump(sinh(8));
+var_dump(sinh(9));
+var_dump(sinh(10));
+var_dump(sinh(11));
+var_dump(sinh(13));
+var_dump(sinh(14));
+?>
+--EXPECT--
+-- reference points already correct on every platform --
+float(0)
+float(1.1752011936438014)
+float(12077476.376787629)
+-- inputs the FPU clamp gets wrong --
+float(10.017874927409903)
+float(74.20321057778875)
+float(201.71315737027922)
+float(548.3161232732465)
+float(1490.4788257895502)
+float(4051.54190208279)
+float(11013.232874703393)
+float(29937.07084924806)
+float(221206.6960033301)
+float(601302.1420819727)