new file mode 100644
@@ -0,0 +1,38 @@
+From 25f686e0da423326a74fe16c603b6b6b75857fa4 Mon Sep 17 00:00:00 2001
+From: Helmut Grohne <helmut@subdivi.de>
+Date: Sun, 16 Mar 2025 20:07:19 +0100
+Subject: [PATCH] sphere: avoid integer underflow
+
+Source: https://salsa.debian.org/lts-team/packages/sox/-/blob/debian/14.4.2+git20190427-1+deb10u3/debian/patches/CVE-2021-40426.patch
+
+CVE: CVE-2021-40426
+Upstream-Status: Inactive-Upstream [lastrelease: 2015]
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ src/sphere.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/src/sphere.c b/src/sphere.c
+index a3fd1c64..9544d160 100644
+--- a/src/sphere.c
++++ b/src/sphere.c
+@@ -63,7 +63,8 @@ static int start_read(sox_format_t * ft)
+ return (SOX_EOF);
+ }
+
+- header_size -= (strlen(buf) + 1);
++ bytes_read = strlen(buf);
++ header_size -= bytes_read >= header_size ? header_size : bytes_read + 1;
+
+ while (strncmp(buf, "end_head", (size_t)8) != 0) {
+ if (strncmp(buf, "sample_n_bytes", (size_t)14) == 0)
+@@ -105,7 +106,8 @@ static int start_read(sox_format_t * ft)
+ return (SOX_EOF);
+ }
+
+- header_size -= (strlen(buf) + 1);
++ bytes_read = strlen(buf);
++ header_size -= bytes_read >= header_size ? header_size : bytes_read + 1;
+ }
+
+ if (!bytes_per_sample)
@@ -32,6 +32,7 @@ SRC_URI = "git://git.code.sf.net/p/sox/code;protocol=https;branch=master \
file://CVE-2021-3643_CVE-2021-23210.patch \
file://CVE-2021-23159_CVE-2021-2317.patch \
file://CVE-2021-33844.patch \
+ file://CVE-2021-40426.patch \
"
# last release was in 2015, use latest hash from 2024-05-30