diff --git a/doc/pcre2_jit_stack_create.3 b/doc/pcre2_jit_stack_create.3
index f0b29f0..d332b72 100644
--- a/doc/pcre2_jit_stack_create.3
+++ b/doc/pcre2_jit_stack_create.3
@@ -22,7 +22,8 @@ allocation. The result can be passed to the JIT run-time code by calling
 \fBpcre2_jit_stack_assign()\fP to associate the stack with a compiled pattern,
 which can then be processed by \fBpcre2_match()\fP or \fBpcre2_jit_match()\fP.
 A maximum stack size of 512KiB to 1MiB should be more than enough for any
-pattern. For more details, see the
+pattern. If the stack couldn't be allocated or the values passed were not
+reasonable, NULL will be returned. For more details, see the
 .\" HREF
 \fBpcre2jit\fP
 .\"
diff --git a/src/pcre2_jit_misc.c b/src/pcre2_jit_misc.c
index ec924e0..d532df9 100644
--- a/src/pcre2_jit_misc.c
+++ b/src/pcre2_jit_misc.c
@@ -135,7 +135,7 @@ return NULL;
 
 pcre2_jit_stack *jit_stack;
 
-if (startsize < 1 || maxsize < 1)
+if (startsize == 0 || maxsize == 0 || maxsize > PCRE2_SIZE_MAX - STACK_GROWTH_RATE)
   return NULL;
 if (startsize > maxsize)
   startsize = maxsize;