diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index 8a3793b9072b78..7d1591f241c244 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -1297,6 +1297,10 @@ def testGetServBy(self):
         self.assertRaises(OverflowError, socket.getservbyport, -1)
         self.assertRaises(OverflowError, socket.getservbyport, 65536)
 
+    def testGetProtoByName(self):
+        self.assertEqual(socket.getprotobyname('tcp'), 6)
+        self.assertRaises(OSError, socket.getprotobyname, 'non-existent proto')
+
     def testDefaultTimeout(self):
         # Testing default timeout
         # The default timeout should initially be None
diff --git a/Misc/NEWS.d/next/Library/2025-04-17-00-14-41.gh-issue-127081.aEM3Hk.rst b/Misc/NEWS.d/next/Library/2025-04-17-00-14-41.gh-issue-127081.aEM3Hk.rst
new file mode 100644
index 00000000000000..225f3be417ce0e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-04-17-00-14-41.gh-issue-127081.aEM3Hk.rst
@@ -0,0 +1,2 @@
+Fix thread safety issues with getservbyname, getservbyport, and
+getprotobyname.
diff --git a/Misc/NEWS.d/next/Library/2025-04-21-01-00-47.gh-issue-127081.o56pE1.rst b/Misc/NEWS.d/next/Library/2025-04-21-01-00-47.gh-issue-127081.o56pE1.rst
new file mode 100644
index 00000000000000..9e82771130b45a
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-04-21-01-00-47.gh-issue-127081.o56pE1.rst
@@ -0,0 +1,3 @@
+Fix libc thread safety issues with :mod:`socket` by replacing
+``getservbyname``, ``getservbyport``, and ``getprotobyname`` with ``*_r``
+re-entrant versions.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index f55a9583b8586a..dbdf31e1828667 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -6282,7 +6282,7 @@ Return the true host name, a list of aliases, and a list of IP addresses,\n\
 for a host.  The host argument is a string giving a host name or IP number.");
 #endif
 
-#ifdef HAVE_GETSERVBYNAME
+#if defined(HAVE_GETSERVBYNAME_R) || defined (HAVE_GETSERVBYNAME)
 /* Python interface to getservbyname(name).
    This only returns the port number, since the other info is already
    known or not useful (like the list of aliases). */
@@ -6292,6 +6292,12 @@ static PyObject *
 socket_getservbyname(PyObject *self, PyObject *args)
 {
     const char *name, *proto=NULL;
+#ifdef HAVE_GETSERVBYNAME_R
+    struct servent entry;
+    /* TODO: The man page says 1024 is usually enough, start with that and
+       retry if insufficient? */
+    char buf[16384];
+#endif
     struct servent *sp;
     if (!PyArg_ParseTuple(args, "s|s:getservbyname", &name, &proto))
         return NULL;
@@ -6301,7 +6307,11 @@ socket_getservbyname(PyObject *self, PyObject *args)
     }
 
     Py_BEGIN_ALLOW_THREADS
+#ifdef HAVE_GETSERVBYNAME_R
+    getservbyname_r(name, proto, &entry, buf, sizeof(buf), &sp);
+#else
     sp = getservbyname(name, proto);
+#endif
     Py_END_ALLOW_THREADS
     if (sp == NULL) {
         PyErr_SetString(PyExc_OSError, "service/proto not found");
@@ -6318,7 +6328,7 @@ The optional protocol name, if given, should be 'tcp' or 'udp',\n\
 otherwise any protocol will match.");
 #endif
 
-#ifdef HAVE_GETSERVBYPORT
+#if defined(HAVE_GETSERVBYPORT_R) || defined (HAVE_GETSERVBYPORT)
 /* Python interface to getservbyport(port).
    This only returns the service name, since the other info is already
    known or not useful (like the list of aliases). */
@@ -6329,6 +6339,12 @@ socket_getservbyport(PyObject *self, PyObject *args)
 {
     int port;
     const char *proto=NULL;
+#ifdef HAVE_GETSERVBYPORT_R
+    struct servent entry;
+    /* TODO: The man page says 1024 is usually enough, start with that and
+       retry if insufficient? */
+    char buf[16384];
+#endif
     struct servent *sp;
     if (!PyArg_ParseTuple(args, "i|s:getservbyport", &port, &proto))
         return NULL;
@@ -6344,7 +6360,11 @@ socket_getservbyport(PyObject *self, PyObject *args)
     }
 
     Py_BEGIN_ALLOW_THREADS
+#ifdef HAVE_GETSERVBYPORT_R
+    getservbyport_r(htons((short)port), proto, &entry, buf, sizeof(buf), &sp);
+#else
     sp = getservbyport(htons((short)port), proto);
+#endif
     Py_END_ALLOW_THREADS
     if (sp == NULL) {
         PyErr_SetString(PyExc_OSError, "port/proto not found");
@@ -6361,7 +6381,7 @@ The optional protocol name, if given, should be 'tcp' or 'udp',\n\
 otherwise any protocol will match.");
 #endif
 
-#ifdef HAVE_GETPROTOBYNAME
+#if defined(HAVE_GETPROTOBYNAME_R) || defined (HAVE_GETPROTOBYNAME)
 /* Python interface to getprotobyname(name).
    This only returns the protocol number, since the other info is
    already known or not useful (like the list of aliases). */
@@ -6371,11 +6391,21 @@ static PyObject *
 socket_getprotobyname(PyObject *self, PyObject *args)
 {
     const char *name;
+#ifdef HAVE_GETPROTOBYNAME_R
+    struct protoent entry;
+    /* TODO: The man page says 1024 is usually enough, start with that and
+       retry if insufficient? */
+    char buf[16384];
+#endif
     struct protoent *sp;
     if (!PyArg_ParseTuple(args, "s:getprotobyname", &name))
         return NULL;
     Py_BEGIN_ALLOW_THREADS
+#ifdef HAVE_GETPROTOBYNAME_R
+    getprotobyname_r(name, &entry, buf, sizeof(buf), &sp);
+#else
     sp = getprotobyname(name);
+#endif
     Py_END_ALLOW_THREADS
     if (sp == NULL) {
         PyErr_SetString(PyExc_OSError, "protocol not found");
@@ -7428,15 +7458,15 @@ static PyMethodDef socket_methods[] = {
     {"sethostname",             socket_sethostname,
      METH_VARARGS,  sethostname_doc},
 #endif
-#ifdef HAVE_GETSERVBYNAME
+#if defined(HAVE_GETSERVBYNAME_R) || defined (HAVE_GETSERVBYNAME)
     {"getservbyname",           socket_getservbyname,
      METH_VARARGS, getservbyname_doc},
 #endif
-#ifdef HAVE_GETSERVBYPORT
+#if defined(HAVE_GETSERVBYPORT_R) || defined (HAVE_GETSERVBYPORT)
     {"getservbyport",           socket_getservbyport,
      METH_VARARGS, getservbyport_doc},
 #endif
-#ifdef HAVE_GETPROTOBYNAME
+#if defined (HAVE_GETPROTOBYNAME_R) || defined (HAVE_GETPROTOBYNAME)
     {"getprotobyname",          socket_getprotobyname,
      METH_VARARGS, getprotobyname_doc},
 #endif
diff --git a/configure b/configure
index decb8f2449d162..0083730ae3c535 100755
--- a/configure
+++ b/configure
@@ -22615,6 +22615,129 @@ fi
 
 
 
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for getservbyname_r" >&5
+printf %s "checking for getservbyname_r... " >&6; }
+if test ${ac_cv_func_getservbyname_r+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <netdb.h>
+int
+main (void)
+{
+void *x=getservbyname_r
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_func_getservbyname_r=yes
+else case e in #(
+  e) ac_cv_func_getservbyname_r=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_getservbyname_r" >&5
+printf "%s\n" "$ac_cv_func_getservbyname_r" >&6; }
+  if test "x$ac_cv_func_getservbyname_r" = xyes
+then :
+
+printf "%s\n" "#define HAVE_GETSERVBYNAME_R 1" >>confdefs.h
+
+fi
+
+
+
+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for getservbyport_r" >&5
+printf %s "checking for getservbyport_r... " >&6; }
+if test ${ac_cv_func_getservbyport_r+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <netdb.h>
+int
+main (void)
+{
+void *x=getservbyport_r
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_func_getservbyport_r=yes
+else case e in #(
+  e) ac_cv_func_getservbyport_r=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_getservbyport_r" >&5
+printf "%s\n" "$ac_cv_func_getservbyport_r" >&6; }
+  if test "x$ac_cv_func_getservbyport_r" = xyes
+then :
+
+printf "%s\n" "#define HAVE_GETSERVBYPORT_R 1" >>confdefs.h
+
+fi
+
+
+
+
+
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for getprotobyname_r" >&5
+printf %s "checking for getprotobyname_r... " >&6; }
+if test ${ac_cv_func_getprotobyname_r+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <netdb.h>
+int
+main (void)
+{
+void *x=getprotobyname_r
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_func_getprotobyname_r=yes
+else case e in #(
+  e) ac_cv_func_getprotobyname_r=no ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_getprotobyname_r" >&5
+printf "%s\n" "$ac_cv_func_getprotobyname_r" >&6; }
+  if test "x$ac_cv_func_getprotobyname_r" = xyes
+then :
+
+printf "%s\n" "#define HAVE_GETPROTOBYNAME_R 1" >>confdefs.h
+
+fi
+
+
+
+
+
 
 
 
diff --git a/configure.ac b/configure.ac
index 004797b5233c20..6a53fe27c27c37 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5395,6 +5395,9 @@ PY_CHECK_NETDB_FUNC([getservbyport])
 PY_CHECK_NETDB_FUNC([gethostbyname])
 PY_CHECK_NETDB_FUNC([gethostbyaddr])
 PY_CHECK_NETDB_FUNC([getprotobyname])
+PY_CHECK_NETDB_FUNC([getservbyname_r])
+PY_CHECK_NETDB_FUNC([getservbyport_r])
+PY_CHECK_NETDB_FUNC([getprotobyname_r])
 
 dnl PY_CHECK_SOCKET_FUNC(FUNCTION)
 AC_DEFUN([PY_CHECK_SOCKET_FUNC], [PY_CHECK_FUNC([$1], [
diff --git a/pyconfig.h.in b/pyconfig.h.in
index aa086d49e90a5b..fe240cfda71f0b 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -557,6 +557,9 @@
 /* Define if you have the 'getprotobyname' function. */
 #undef HAVE_GETPROTOBYNAME
 
+/* Define if you have the 'getprotobyname_r' function. */
+#undef HAVE_GETPROTOBYNAME_R
+
 /* Define to 1 if you have the 'getpwent' function. */
 #undef HAVE_GETPWENT
 
@@ -587,9 +590,15 @@
 /* Define if you have the 'getservbyname' function. */
 #undef HAVE_GETSERVBYNAME
 
+/* Define if you have the 'getservbyname_r' function. */
+#undef HAVE_GETSERVBYNAME_R
+
 /* Define if you have the 'getservbyport' function. */
 #undef HAVE_GETSERVBYPORT
 
+/* Define if you have the 'getservbyport_r' function. */
+#undef HAVE_GETSERVBYPORT_R
+
 /* Define to 1 if you have the 'getsid' function. */
 #undef HAVE_GETSID