diff --git a/nettle-3.7-chacha-counter-ppc64.patch b/nettle-3.7-chacha-counter-ppc64.patch
new file mode 100644
index 0000000..7f9f103
--- /dev/null
+++ b/nettle-3.7-chacha-counter-ppc64.patch
@@ -0,0 +1,51 @@
+From 64837b2e433e2b99b893683949bad3a99acab38f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
+Date: Wed, 10 Feb 2021 11:22:23 +0100
+Subject: [PATCH] Fix chacha counter update for _4core variants.
+
+---
+ ChangeLog      |  4 ++++
+ chacha-crypt.c | 10 +++++++---
+ 2 files changed, 11 insertions(+), 3 deletions(-)
+
+diff --git a/chacha-crypt.c b/chacha-crypt.c
+index 081ebcf4..1fdfc813 100644
+--- a/chacha-crypt.c
++++ b/chacha-crypt.c
+@@ -80,13 +80,16 @@ _nettle_chacha_crypt_4core(struct chacha_ctx *ctx,
+   while (length > 2*CHACHA_BLOCK_SIZE)
+     {
+       _nettle_chacha_4core (x, ctx->state, CHACHA_ROUNDS);
+-      ctx->state[12] += 4;
+-      ctx->state[13] += (ctx->state[12] < 4);
+       if (length <= 4*CHACHA_BLOCK_SIZE)
+ 	{
++	  uint32_t incr = 3 + (length > 3*CHACHA_BLOCK_SIZE);
++	  ctx->state[12] += incr;
++	  ctx->state[13] += (ctx->state[12] < incr);
+ 	  memxor3 (dst, src, x, length);
+ 	  return;
+ 	}
++      ctx->state[12] += 4;
++      ctx->state[13] += (ctx->state[12] < 4);
+       memxor3 (dst, src, x, 4*CHACHA_BLOCK_SIZE);
+ 
+       length -= 4*CHACHA_BLOCK_SIZE;
+@@ -200,12 +203,13 @@ _nettle_chacha_crypt32_4core(struct chacha_ctx *ctx,
+   while (length > 2*CHACHA_BLOCK_SIZE)
+     {
+       _nettle_chacha_4core32 (x, ctx->state, CHACHA_ROUNDS);
+-      ctx->state[12] += 4;
+       if (length <= 4*CHACHA_BLOCK_SIZE)
+ 	{
++	  ctx->state[12] += 3 + (length > 3*CHACHA_BLOCK_SIZE);
+ 	  memxor3 (dst, src, x, length);
+ 	  return;
+ 	}
++      ctx->state[12] += 4;
+       memxor3 (dst, src, x, 4*CHACHA_BLOCK_SIZE);
+ 
+       length -= 4*CHACHA_BLOCK_SIZE;
+-- 
+2.29.2
+
diff --git a/nettle.spec b/nettle.spec
index d8cd29e..b82fd68 100644
--- a/nettle.spec
+++ b/nettle.spec
@@ -15,7 +15,7 @@
 
 Name:           nettle
 Version:        3.7
-Release:        2%{?dist}
+Release:        3%{?dist}
 Summary:        A low-level cryptographic library
 
 License:        LGPLv3+ or GPLv2+
@@ -28,6 +28,8 @@ Source2:	nettle-3.5-remove-ecc-testsuite.patch
 %endif
 Patch0:		nettle-3.6-remove-ecc-testsuite.patch
 Patch1:		nettle-3.4-annocheck.patch
+# https://lists.lysator.liu.se/pipermail/nettle-bugs/2021/009423.html
+Patch2:		nettle-3.7-chacha-counter-ppc64.patch
 
 BuildRequires: make
 BuildRequires:  gcc
@@ -171,6 +173,9 @@ make check
 
 
 %changelog
+* Wed Feb 10 2021 Daiki Ueno <dueno@redhat.com> - 3.7-3
+- Port a fix for chacha counter issue on ppc64le
+
 * Tue Jan 26 2021 Fedora Release Engineering <releng@fedoraproject.org> - 3.7-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild