diff --git a/cgminer.c b/cgminer.c
index bddce1c3..04ba4687 100644
--- a/cgminer.c
+++ b/cgminer.c
@@ -5068,7 +5068,7 @@ static struct work *clone_work(struct work *work)
 
 static void gen_hash(unsigned char *data, unsigned char *hash, int len)
 {
-	unsigned char hash1[36];
+	unsigned char hash1[32];
 
 	sha2(data, len, hash1, false);
 	sha2(hash1, 32, hash, false);
@@ -5080,7 +5080,7 @@ static void gen_hash(unsigned char *data, unsigned char *hash, int len)
  * cover a huge range of difficulty targets, though not all 256 bits' worth */
 static void set_work_target(struct work *work, int diff)
 {
-	unsigned char rtarget[36], target[36];
+	unsigned char rtarget[32], target[32];
 	uint64_t *data64, h64;
 
 	h64 = diffone;
@@ -5103,9 +5103,9 @@ static void set_work_target(struct work *work, int diff)
  * other means to detect when the pool has died in stratum_thread */
 static void gen_stratum_work(struct pool *pool, struct work *work)
 {
-	unsigned char *coinbase, merkle_root[36], merkle_sha[68], *merkle_hash;
+	unsigned char *coinbase, merkle_root[32], merkle_sha[64], *merkle_hash;
 	int len, cb1_len, n1_len, cb2_len, i;
-	char header[260], *nonce2;
+	char header[256], *nonce2;
 	uint32_t *data32, *swap32;
 
 	memset(work->job_id, 0, 64);
@@ -5131,7 +5131,7 @@ static void gen_stratum_work(struct pool *pool, struct work *work)
 	gen_hash(coinbase, merkle_root, len);
 	memcpy(merkle_sha, merkle_root, 32);
 	for (i = 0; i < pool->swork.merkles; i++) {
-		unsigned char merkle_bin[36];
+		unsigned char merkle_bin[32];
 
 		hex2bin(merkle_bin, pool->swork.merkle[i], 32);
 		memcpy(merkle_sha + 32, merkle_bin, 32);