Find apps with unsafe Sparkle versions

sparklecheck.sh

#!/bin/bash
set -o pipefail
IFS=$'\n'
REPORT=''

checkapp() {
    local APPPATH=$1
    local PLIST="$APPPATH/Contents/Info.plist"
    local SPARKLEPLIST="$APPPATH/Contents/Frameworks/Sparkle.framework/Resources/Info.plist"
    local SPARKLEBIN="$APPPATH/Contents/Frameworks/Sparkle.framework/Sparkle"
    local VER=$(defaults read "$PLIST" CFBundleShortVersionString 2>/dev/null || defaults read "$PLIST" CFBundleVersion 2>/dev/null)
    local APP="$(basename -s .app "$APPPATH") $VER"
    FEED=$(defaults read "$PLIST" SUFeedURL 2>/dev/null)
    local RESULT=$?
    if [ -d "$APPPATH/Contents/_MASReceipt" -a ! -e "$SPARKLEBIN" ]; then
        echo "ok: $APP does not use Sparkle";
    elif [ "$RESULT" -ne 0 -a ! -e "$SPARKLEPLIST" ]; then
        echo "ok: $APP does not seem to use Sparkle";
    elif [[ $FEED == "https://"* ]]; then
        echo "ok: $APP uses HTTPS for updates - safe";
    elif fgrep 2>/dev/null -q "about:blank" "$SPARKLEBIN"; then
        echo "ok: $APP has a patched version Sparkle - safe"
    else
        SPARKLEVER=$(defaults read "$SPARKLEPLIST" CFBundleVersion 2>/dev/null)
        local RESULT=$?
        if [ $RESULT -eq 0 -a -n "$FEED" ]; then
            REPORT+="
!!: $APP uses insecure feed URL '$FEED' and an unpatched version of Sparkle ($SPARKLEVER) - it is UNSAFE"
        elif [ $RESULT -ne 0 ]; then
            REPORT+="
!!: $APP uses insecure feed URL '$FEED' and an unknown version of Sparkle - may be UNSAFE"
        else
            echo "!!: $APP uses unknown feed URL and an unknown version of Sparkle - unable to tell"
        fi

    fi
}

for i in $({ mdfind kind:application; find /Applications -maxdepth 2 -name '*.app'; } | sort -u ); do
    checkapp "$i"
done

if [ -n "$REPORT" ]; then
echo "
Unsafe applications found!
$REPORT

Please ask the apps' developers to update Sparkle to the secure version,
as described at: https://sparkle-project.org/documentation/security
"
fi

What us main script for command line?

this one?
for i in $({ mdfind kind:application; find /Applications -maxdepth 2 -name '*.app'; } | sort -u ); do
checkapp "$i"
done

@Kosmic-Halo You just run ./sparklecheck.sh.

Do you recommend single user mode for this? Or just the regular terminal?

This won't work in single user mode.