diff --git a/lib/libc/stdlib/strtol.c b/lib/libc/stdlib/strtol.c
index 10d7425c0f8974..07728944f4d76b 100644
--- a/lib/libc/stdlib/strtol.c
+++ b/lib/libc/stdlib/strtol.c
@@ -87,7 +87,7 @@ strtol(nptr, endptr, base)
 	if (base == 0)
 		base = c == '0' ? 8 : 10;
 	acc = any = 0;
-	if (base < 2)
+	if (base < 2 || base > 35)
 		goto noconv;
 
 	/*
diff --git a/lib/libc/stdlib/strtoll.c b/lib/libc/stdlib/strtoll.c
index 5d656c1bee3c9f..2992ec83f1e864 100644
--- a/lib/libc/stdlib/strtoll.c
+++ b/lib/libc/stdlib/strtoll.c
@@ -86,7 +86,7 @@ strtoll(nptr, endptr, base)
 	if (base == 0)
 		base = c == '0' ? 8 : 10;
 	acc = any = 0;
-	if (base < 2)
+	if (base < 2 || base > 35)
 		goto noconv;
 
 	/*
diff --git a/lib/libc/stdlib/strtoul.c b/lib/libc/stdlib/strtoul.c
index e952663c533e4f..e9046b0d285a18 100644
--- a/lib/libc/stdlib/strtoul.c
+++ b/lib/libc/stdlib/strtoul.c
@@ -84,7 +84,7 @@ strtoul(nptr, endptr, base)
 	if (base == 0)
 		base = c == '0' ? 8 : 10;
 	acc = any = 0;
-	if (base < 2)
+	if (base < 2 || base > 35)
 		goto noconv;
 
 	cutoff = ULONG_MAX / base;
diff --git a/lib/libc/stdlib/strtoull.c b/lib/libc/stdlib/strtoull.c
index 15a097221188fe..3e9b40077d6fef 100644
--- a/lib/libc/stdlib/strtoull.c
+++ b/lib/libc/stdlib/strtoull.c
@@ -84,7 +84,7 @@ strtoull(nptr, endptr, base)
 	if (base == 0)
 		base = c == '0' ? 8 : 10;
 	acc = any = 0;
-	if (base < 2)
+	if (base < 2 || base > 35)
 		goto noconv;
 
 	cutoff = ULLONG_MAX / base;