diff --git a/realalg/base_algebraic.py b/realalg/base_algebraic.py
index ad4218e..8e9cc6f 100644
--- a/realalg/base_algebraic.py
+++ b/realalg/base_algebraic.py
@@ -6,6 +6,8 @@
 from functools import total_ordering
 from math import log10 as log
 from numbers import Integral
+import sys
+
 import sympy as sp
 
 from .interval import Interval
@@ -14,6 +16,12 @@
 sp_QQ_x = sp.QQ.old_poly_ring(sp_x)
 LOG_2 = log(2)
 
+# By default, Python will only convert a decimal string of length at
+# most 4300 to an integer to protect against DDOS attacks; not relevant
+# here (CVE-2020-10735).
+if hasattr(sys, 'set_int_max_str_digits'):
+    sys.set_int_max_str_digits(0)
+
 def log_plus(x):
     ''' Return the height of the number ``x``. '''
     return log(max(1, abs(x)))