diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f35a70d8f9..115bf2c654 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -151,16 +151,18 @@ jobs:
           TOOLCHAIN_PATH=snapshots
 
           if [ -n "${{ github.base_ref }}" ]; then
-            if echo "${{ github.base_ref }}" | grep -q -E 'openwrt-[0-9][0-9]\.[0-9][0-9]'; then
-              major_ver="$(echo ${{ github.base_ref }} | sed 's/openwrt-/v/')"
+            if echo "${{ github.base_ref }}" | grep -q -E '^openwrt-[0-9][0-9]\.[0-9][0-9]$'; then
+              major_ver="$(echo ${{ github.base_ref }} | sed 's/^openwrt-/v/')"
             fi
           elif [ "${{ github.ref_type }}" = "branch" ]; then
-            if echo "${{ github.ref_name }}" | grep -q -E 'openwrt-[0-9][0-9]\.[0-9][0-9]-'; then
-              major_ver="$(echo ${{ github.ref_name }} | sed 's/openwrt-\([0-9][0-9]\.[0-9][0-9]\)-.*/v\1/')"
+            if echo "${{ github.ref_name }}" | grep -q -E '^openwrt-[0-9][0-9]\.[0-9][0-9]$'; then
+              major_ver="$(echo ${{ github.ref_name }} | sed 's/^openwrt-/v/')"
+            elif echo "${{ github.ref_name }}" | grep -q -E '^openwrt-[0-9][0-9]\.[0-9][0-9]-'; then
+              major_ver="$(echo ${{ github.ref_name }} | sed 's/^openwrt-\([0-9][0-9]\.[0-9][0-9]\)-.*/v\1/')"
             fi
           elif [ "${{ github.ref_type }}" = "tag" ]; then
-            if echo "${{ github.ref_name }}" | grep -q -E 'v[0-9][0-9]\.[0-9][0-9]\..+'; then
-              major_ver="$(sed 's/\(v[0-9][0-9]\.[0-9][0-9]\)\..\+/\1/')"
+            if echo "${{ github.ref_name }}" | grep -q -E '^v[0-9][0-9]\.[0-9][0-9]\..+'; then
+              major_ver="$(echo ${{ github.ref_name }} | sed 's/^\(v[0-9][0-9]\.[0-9][0-9]\)\..\+/\1/')"
             fi
           fi