diff --git a/meta/recipes-devtools/flex/flex/0001-lib-malloc.c-match-malloc-signature-to-its-use.patch b/meta/recipes-devtools/flex/flex/0001-lib-malloc.c-match-malloc-signature-to-its-use.patch
new file mode 100644
index 0000000000..7adeedcaa6
--- /dev/null
+++ b/meta/recipes-devtools/flex/flex/0001-lib-malloc.c-match-malloc-signature-to-its-use.patch
@@ -0,0 +1,37 @@
+From bf254c75b1e0d2641ebbd7fc85fb183f36a62ea7 Mon Sep 17 00:00:00 2001
+From: Richard Barnes <rbarnes@umn.edu>
+Date: Wed, 2 Oct 2024 10:35:09 -0700
+Subject: [PATCH] Match `malloc` signature to its use
+
+The gnulib fallback declares "void *malloc ();" with an empty parameter
+list and calls it with one argument. That meant "unspecified" in C89 and
+means "none" in C23, so a compiler defaulting to C23 -- GCC 15 and later
+-- rejects the call:
+
+  lib/malloc.c:16:15: error: too many arguments to function 'malloc';
+                             expected 0, have 1
+
+The file is built by stage1flex with the build host's compiler before
+flex can build itself, so neither CFLAGS nor BUILD_CFLAGS reaches that
+command line and no flag in the recipe can silence it.
+
+Upstream-Status: Backport [https://github.com/westes/flex/commit/bf254c75b1e0d2641ebbd7fc85fb183f36a62ea7]
+
+Signed-off-by: Aurelien DESBRIERES <aurelien@hackers.camp>
+---
+ lib/malloc.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/malloc.c b/lib/malloc.c
+index 75e8ef97c..701b9b39d 100755
+--- a/lib/malloc.c
++++ b/lib/malloc.c
+@@ -3,7 +3,7 @@
+      
+      #include <sys/types.h>
+      
+-     void *malloc ();
++     void *malloc (size_t n);
+      
+      /* Allocate an N-byte block of memory from the heap.
+         If N is zero, allocate a 1-byte block.  */
diff --git a/meta/recipes-devtools/flex/flex_2.6.4.bb b/meta/recipes-devtools/flex/flex_2.6.4.bb
index 793a935962..3b652bda80 100644
--- a/meta/recipes-devtools/flex/flex_2.6.4.bb
+++ b/meta/recipes-devtools/flex/flex_2.6.4.bb
@@ -19,6 +19,7 @@ SRC_URI = "${GITHUB_BASE_URI}/download/v${PV}/flex-${PV}.tar.gz \
            file://check-funcs.patch \
            file://0001-Emit-no-line-directives-if-gen_line_dirs-is-false.patch \
            file://0001-build-tests-add-missing-parser-scanner-dependencies.patch \
+           file://0001-lib-malloc.c-match-malloc-signature-to-its-use.patch \
            "
 
 SRC_URI[md5sum] = "2882e3179748cc9f9c23ec593d6adc8d"