diff --git a/gnu/local.mk b/gnu/local.mk
index 8c9883a5e2..ae4a59af0b 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -575,6 +575,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/eudev-conflicting-declaration.patch	\
   %D%/packages/patches/evilwm-lost-focus-bug.patch		\
   %D%/packages/patches/expat-CVE-2016-0718-fix-regression.patch	\
+  %D%/packages/patches/exim-CVE-2017-1000369.patch		\
   %D%/packages/patches/fabric-tests.patch			\
   %D%/packages/patches/fastcap-mulGlobal.patch			\
   %D%/packages/patches/fastcap-mulSetup.patch			\
diff --git a/gnu/packages/mail.scm b/gnu/packages/mail.scm
index f4003d7391..7fde203593 100644
--- a/gnu/packages/mail.scm
+++ b/gnu/packages/mail.scm
@@ -1004,6 +1004,7 @@ delivery.")
                                  version ".tar.bz2")
                   (string-append "ftp://ftp.exim.org/pub/exim/exim4/old/exim-"
                                  version ".tar.bz2")))
+       (patches (search-patches "exim-CVE-2017-1000369.patch"))
        (sha256
         (base32
          "050m2gjzpc6vyik458h1j0vi8bxplkzjsyndkyd2y394i569kdyl"))))
diff --git a/gnu/packages/patches/exim-CVE-2017-1000369.patch b/gnu/packages/patches/exim-CVE-2017-1000369.patch
new file mode 100644
index 0000000000..a67a8afb0e
--- /dev/null
+++ b/gnu/packages/patches/exim-CVE-2017-1000369.patch
@@ -0,0 +1,59 @@
+Fix CVE-2017-1000369:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-1000369
+https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt
+
+Patch adapted from upstream source repository:
+
+https://git.exim.org/exim.git/commit/65e061b76867a9ea7aeeb535341b790b90ae6c21
+
+From 65e061b76867a9ea7aeeb535341b790b90ae6c21 Mon Sep 17 00:00:00 2001
+From: "Heiko Schlittermann (HS12-RIPE)" <hs@schlittermann.de>
+Date: Wed, 31 May 2017 23:08:56 +0200
+Subject: [PATCH] Cleanup (prevent repeated use of -p/-oMr to avoid mem leak)
+
+---
+ doc/doc-docbook/spec.xfpt |  3 ++-
+ src/src/exim.c            | 19 +++++++++++++++++--
+ 2 files changed, 19 insertions(+), 3 deletions(-)
+
+diff --git a/src/src/exim.c b/src/src/exim.c
+index 67583e58..88e11977 100644
+--- a/src/exim.c
++++ b/src/exim.c
+@@ -3106,7 +3106,14 @@ for (i = 1; i < argc; i++)
+ 
+       /* -oMr: Received protocol */
+ 
+-      else if (Ustrcmp(argrest, "Mr") == 0) received_protocol = argv[++i];
++      else if (Ustrcmp(argrest, "Mr") == 0)
++
++        if (received_protocol)
++          {
++          fprintf(stderr, "received_protocol is set already\n");
++          exit(EXIT_FAILURE);
++          }
++        else received_protocol = argv[++i];
+ 
+       /* -oMs: Set sender host name */
+ 
+@@ -3202,7 +3209,15 @@ for (i = 1; i < argc; i++)
+ 
+     if (*argrest != 0)
+       {
+-      uschar *hn = Ustrchr(argrest, ':');
++      uschar *hn;
++
++      if (received_protocol)
++        {
++        fprintf(stderr, "received_protocol is set already\n");
++        exit(EXIT_FAILURE);
++        }
++
++      hn = Ustrchr(argrest, ':');
+       if (hn == NULL)
+         {
+         received_protocol = argrest;
+-- 
+2.13.1
+