From 77fc607ca17f652e988430a79d609e3080900e93 Mon Sep 17 00:00:00 2001
From: PeterM <1434309+petesmc@users.noreply.github.com>
Date: Sun, 10 Aug 2025 21:19:54 +0800
Subject: [PATCH] Fix potential free of null pointer in stringlist_delete

---
 CHANGES.md             | 1 +
 fitsio/fitsio_pywrap.c | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 8aafd1fa..3ca0859d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -7,6 +7,7 @@ Bug Fixes
     - Fix writing and reading of string columns with length
       1 vectors in numpy 2.
     - Fix building against NumPy 2.3.0.
+    - Fix potential free of null pointer in stringlist_delete
 
 version 1.2.5
 -------------
diff --git a/fitsio/fitsio_pywrap.c b/fitsio/fitsio_pywrap.c
index 957643dd..e216db06 100644
--- a/fitsio/fitsio_pywrap.c
+++ b/fitsio/fitsio_pywrap.c
@@ -305,10 +305,12 @@ static struct stringlist* stringlist_delete(struct stringlist* slist) {
         size_t i=0;
         if (slist->data != NULL) {
             for (i=0; i < slist->size; i++) {
-                free(slist->data[i]);
+                if (slist->data[i] != NULL) {
+                    free(slist->data[i]);
+                }
             }
+            free(slist->data);
         }
-        free(slist->data);
         free(slist);
     }
     return NULL;