diff --git a/test/smp/cmake/coverage.sh b/test/smp/cmake/coverage.sh
index d35284f57..a7312e1f4 100755
--- a/test/smp/cmake/coverage.sh
+++ b/test/smp/cmake/coverage.sh
@@ -16,5 +16,31 @@ set -e
 cd $(dirname $0)
 threadx_smp=$(realpath ../../../common_smp/src)
 mkdir -p coverage_report/$1
-gcovr --object-directory=build/$1/threadx_smp/CMakeFiles/threadx_smp.dir/$threadx_smp -r build/$1 -f ../../../common_smp/src --xml-pretty --output coverage_report/$1.xml
-gcovr --object-directory=build/$1/threadx_smp/CMakeFiles/threadx_smp.dir/$threadx_smp -r build/$1 -f ../../../common_smp/src --html --html-details --output coverage_report/$1/index.html
+
+# gcov reads a data format tied to the compiler that produced it, so gcov has to match
+# the gcc that built the objects. Since cmake/linux.cmake began honouring CC, taking
+# whatever gcov happens to be first on PATH is no longer safe: building with gcc-14 and
+# reading with gcov-13 gives "version 'B42*', prefer 'B33*'" from gcov, and gcovr turns
+# that into "GCOV returncode was 3" and exits 64. The tests pass and then the coverage
+# step fails with a Python traceback, which reads like a coverage bug rather than a
+# toolchain mismatch.
+#
+# So derive gcov from CC rather than asking the caller to remember both. GCOV still
+# overrides, for a toolchain that does not follow the gcc/gcov naming.
+: "${CC:=gcc}"
+if [ -z "${GCOV:-}" ]; then
+    cc_base=$(basename "$CC")
+    case "$cc_base" in
+        gcc*) GCOV="gcov${cc_base#gcc}" ;;
+        *)    GCOV="gcov" ;;
+    esac
+fi
+
+if ! command -v "$GCOV" >/dev/null 2>&1; then
+    echo "coverage.sh: '$GCOV' not found, derived from CC='$CC'." >&2
+    echo "Install it, or set GCOV to the gcov matching that compiler." >&2
+    exit 1
+fi
+
+gcovr --gcov-executable "$GCOV" --object-directory=build/$1/threadx_smp/CMakeFiles/threadx_smp.dir/$threadx_smp -r build/$1 -f ../../../common_smp/src --xml-pretty --output coverage_report/$1.xml
+gcovr --gcov-executable "$GCOV" --object-directory=build/$1/threadx_smp/CMakeFiles/threadx_smp.dir/$threadx_smp -r build/$1 -f ../../../common_smp/src --html --html-details --output coverage_report/$1/index.html
diff --git a/test/tx/cmake/coverage.sh b/test/tx/cmake/coverage.sh
index 6dda78b38..9b47339e8 100755
--- a/test/tx/cmake/coverage.sh
+++ b/test/tx/cmake/coverage.sh
@@ -15,5 +15,31 @@ set -e
 
 cd $(dirname $0)
 mkdir -p coverage_report/$1
-gcovr --object-directory=build/$1/threadx/CMakeFiles/threadx.dir/common/src -r build/$1 -f ../../../common/src --xml-pretty --output coverage_report/$1.xml
-gcovr --object-directory=build/$1/threadx/CMakeFiles/threadx.dir/common/src -r build/$1 -f ../../../common/src --html --html-details --output coverage_report/$1/index.html
+
+# gcov reads a data format tied to the compiler that produced it, so gcov has to match
+# the gcc that built the objects. Since cmake/linux.cmake began honouring CC, taking
+# whatever gcov happens to be first on PATH is no longer safe: building with gcc-14 and
+# reading with gcov-13 gives "version 'B42*', prefer 'B33*'" from gcov, and gcovr turns
+# that into "GCOV returncode was 3" and exits 64. The tests pass and then the coverage
+# step fails with a Python traceback, which reads like a coverage bug rather than a
+# toolchain mismatch.
+#
+# So derive gcov from CC rather than asking the caller to remember both. GCOV still
+# overrides, for a toolchain that does not follow the gcc/gcov naming.
+: "${CC:=gcc}"
+if [ -z "${GCOV:-}" ]; then
+    cc_base=$(basename "$CC")
+    case "$cc_base" in
+        gcc*) GCOV="gcov${cc_base#gcc}" ;;
+        *)    GCOV="gcov" ;;
+    esac
+fi
+
+if ! command -v "$GCOV" >/dev/null 2>&1; then
+    echo "coverage.sh: '$GCOV' not found, derived from CC='$CC'." >&2
+    echo "Install it, or set GCOV to the gcov matching that compiler." >&2
+    exit 1
+fi
+
+gcovr --gcov-executable "$GCOV" --object-directory=build/$1/threadx/CMakeFiles/threadx.dir/common/src -r build/$1 -f ../../../common/src --xml-pretty --output coverage_report/$1.xml
+gcovr --gcov-executable "$GCOV" --object-directory=build/$1/threadx/CMakeFiles/threadx.dir/common/src -r build/$1 -f ../../../common/src --html --html-details --output coverage_report/$1/index.html