diff --git a/build/pkgs/cmr/checksums.ini b/build/pkgs/cmr/checksums.ini
index b1a9d95fb51..30ce0db487b 100644
--- a/build/pkgs/cmr/checksums.ini
+++ b/build/pkgs/cmr/checksums.ini
@@ -1,5 +1,5 @@
 tarball=cmr-0+VERSION.tar.gz
-sha1=0596debc024061e059a89dfc16d18fde336ece3e
-md5=de719fd28e560277a377a2537e88ab35
-cksum=2141679083
+sha1=3fbd478c6fa49ea009a8ccdfb228e94118113819
+md5=16983436e14cf2c9d722272b58880df9
+cksum=3881313955
 upstream_url=https://github.com/discopt/cmr/archive/VERSION.tar.gz
diff --git a/build/pkgs/cmr/package-version.txt b/build/pkgs/cmr/package-version.txt
index 12efdb61d72..c365825cb78 100644
--- a/build/pkgs/cmr/package-version.txt
+++ b/build/pkgs/cmr/package-version.txt
@@ -1 +1 @@
-9dca928195c4b5bfdb413292eb38e2fb0d388cba
+96f3ccb65e071e73aef7713b5122be8266026349
diff --git a/src/sage/matrix/matrix_cmr_sparse.pyx b/src/sage/matrix/matrix_cmr_sparse.pyx
index 385f099c242..8c3bfbecb1c 100644
--- a/src/sage/matrix/matrix_cmr_sparse.pyx
+++ b/src/sage/matrix/matrix_cmr_sparse.pyx
@@ -461,7 +461,7 @@ cdef class Matrix_cmr_chr_sparse(Matrix_cmr_sparse):
         column_subdivision = []
         row_subdivision.append(first._mat.numRows)
         column_subdivision.append(first._mat.numColumns - 1)
-        characteristic = 0
+        cdef int8_t characteristic = 0
         CMR_CALL(CMRtwoSum(cmr, first._mat, second._mat,
                            CMRcolumnToElement(column), CMRrowToElement(row), characteristic,
                            &sum_mat))