diff --git a/src/acl.c b/src/acl.c
index 6eb6c4bcf..de67b890d 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -1068,19 +1068,24 @@ int ACLSetSelector(aclSelector *selector, const char* op, size_t oplen) {
         int flags = 0;
         size_t offset = 1;
         if (op[0] == '%') {
+            int perm_ok = 1;
             for (; offset < oplen; offset++) {
                 if (toupper(op[offset]) == 'R' && !(flags & ACL_READ_PERMISSION)) {
                     flags |= ACL_READ_PERMISSION;
                 } else if (toupper(op[offset]) == 'W' && !(flags & ACL_WRITE_PERMISSION)) {
                     flags |= ACL_WRITE_PERMISSION;
-                } else if (op[offset] == '~' && flags) {
+                } else if (op[offset] == '~') {
                     offset++;
                     break;
                 } else {
-                    errno = EINVAL;
-                    return C_ERR;
+                    perm_ok = 0;
+                    break;
                 }
             }
+            if (!flags || !perm_ok) {
+                errno = EINVAL;
+                return C_ERR;
+            }
         } else {
             flags = ACL_ALL_PERMISSION;
         }
diff --git a/tests/unit/acl-v2.tcl b/tests/unit/acl-v2.tcl
index 3e6d88f6f..866353d9a 100644
--- a/tests/unit/acl-v2.tcl
+++ b/tests/unit/acl-v2.tcl
@@ -123,9 +123,23 @@ start_server {tags {"acl external:skip"}} {
     }
 
     test {Validate read and write permissions format} {
-        catch {r ACL SETUSER key-permission-RW %~} err
-        set err
-    } {ERR Error in ACL SETUSER modifier '%~': Syntax error}
+        # Regression tests for CVE-2024-51741
+        assert_error "ERR Error in ACL SETUSER modifier '%~': Syntax error" {r ACL SETUSER invalid %~}
+        assert_error "ERR Error in ACL SETUSER modifier '%': Syntax error" {r ACL SETUSER invalid %}
+    }
+
+    test {Validate key permissions format - empty and omitted pattern} {
+        # Empty pattern results with access to only the empty key
+        r ACL SETUSER key-permission-no-key on nopass %RW~ +@all
+        assert_equal "User key-permission-no-key has no permissions to access the 'x' key" [r ACL DRYRUN key-permission-no-key GET x]
+        assert_equal "OK" [r ACL DRYRUN key-permission-no-key GET ""]
+        # This is incorrect syntax, it should have `~`, but we'll allow it for compatibility since it does something
+        r ACL SETUSER key-permission-omit on nopass %RW +@all
+        assert_equal "User key-permission-omit has no permissions to access the 'x' key" [r ACL DRYRUN key-permission-omit GET x]
+        assert_equal "OK" [r ACL DRYRUN key-permission-omit GET ""]
+        # Assert these two are equivalent
+        assert_equal [r ACL GETUSER key-permission-omit] [r ACL GETUSER key-permission-no-key]
+    }
 
     test {Test separate read and write permissions on different selectors are not additive} {
         r ACL SETUSER key-permission-RW-selector on nopass "(%R~read* +@all)" "(%W~write* +@all)"
@@ -467,43 +481,43 @@ start_server {tags {"acl external:skip"}} {
     test {Test sort with ACL permissions} {
         r set v1 1
         r lpush mylist 1
-        
-        r ACL setuser test-sort-acl on nopass (+sort ~mylist)   
+
+        r ACL setuser test-sort-acl on nopass (+sort ~mylist)
         $r2 auth test-sort-acl nopass
-         
-        catch {$r2 sort mylist by v*} e
-        assert_equal "ERR BY option of SORT denied due to insufficient ACL permissions." $e
-        catch {$r2 sort mylist get v*} e
-        assert_equal "ERR GET option of SORT denied due to insufficient ACL permissions." $e 
-        
-        r ACL setuser test-sort-acl (+sort ~mylist ~v*)     
-        catch {$r2 sort mylist by v*} e
-        assert_equal "ERR BY option of SORT denied due to insufficient ACL permissions." $e  
-        catch {$r2 sort mylist get v*} e
-        assert_equal "ERR GET option of SORT denied due to insufficient ACL permissions." $e 
-        
-        r ACL setuser test-sort-acl (+sort ~mylist %W~*)     
+
         catch {$r2 sort mylist by v*} e
         assert_equal "ERR BY option of SORT denied due to insufficient ACL permissions." $e
         catch {$r2 sort mylist get v*} e
         assert_equal "ERR GET option of SORT denied due to insufficient ACL permissions." $e
-       
-        r ACL setuser test-sort-acl (+sort ~mylist %R~*)     
-        assert_equal "1" [$r2 sort mylist by v*]     
-        
+
+        r ACL setuser test-sort-acl (+sort ~mylist ~v*)
+        catch {$r2 sort mylist by v*} e
+        assert_equal "ERR BY option of SORT denied due to insufficient ACL permissions." $e
+        catch {$r2 sort mylist get v*} e
+        assert_equal "ERR GET option of SORT denied due to insufficient ACL permissions." $e
+
+        r ACL setuser test-sort-acl (+sort ~mylist %W~*)
+        catch {$r2 sort mylist by v*} e
+        assert_equal "ERR BY option of SORT denied due to insufficient ACL permissions." $e
+        catch {$r2 sort mylist get v*} e
+        assert_equal "ERR GET option of SORT denied due to insufficient ACL permissions." $e
+
+        r ACL setuser test-sort-acl (+sort ~mylist %R~*)
+        assert_equal "1" [$r2 sort mylist by v*]
+
         # cleanup
         r ACL deluser test-sort-acl
         r del v1 mylist
     }
-    
+
     test {Test DRYRUN with wrong number of arguments} {
         r ACL setuser test-dry-run +@all ~v*
-        
+
         assert_equal "OK" [r ACL DRYRUN test-dry-run SET v v]
-        
+
         catch {r ACL DRYRUN test-dry-run SET v} e
         assert_equal "ERR wrong number of arguments for 'set' command" $e
-        
+
         catch {r ACL DRYRUN test-dry-run SET} e
         assert_equal "ERR wrong number of arguments for 'set' command" $e
     }