diff --git a/typo3/sysext/core/Classes/TypoScript/Parser/TypoScriptParser.php b/typo3/sysext/core/Classes/TypoScript/Parser/TypoScriptParser.php
index ec47e08f4e20af8fde225994e69dd35ac1341ba5..b466df66b135aa3c8f131ad405cbfc10abc889cd 100644
--- a/typo3/sysext/core/Classes/TypoScript/Parser/TypoScriptParser.php
+++ b/typo3/sysext/core/Classes/TypoScript/Parser/TypoScriptParser.php
@@ -355,6 +355,10 @@ class TypoScriptParser
                         $this->multiLineValue[] = $this->raw[$this->rawP - 1];
                     }
                 } elseif ($this->inBrace === 0 && $line[0] === '[') {
+                    if (substr(trim($line), -1, 1) !== ']') {
+                        $this->error('Line ' . ($this->lineNumberOffset + $this->rawP - 1) . ': Invalid condition found, any condition must end with "]": ' . $line);
+                        return $line;
+                    }
                     // Beginning of condition (only on level zero compared to brace-levels
                     if ($this->syntaxHighLight) {
                         $this->regHighLight('condition', $lineP);
diff --git a/typo3/sysext/core/Tests/Unit/TypoScript/Parser/TypoScriptParserTest.php b/typo3/sysext/core/Tests/Unit/TypoScript/Parser/TypoScriptParserTest.php
index 1e73471b7ad42377dee1c41707e08121eddaac72..bdb887ec16244eda6b0f6bf72fb62a14d9ad6eea 100644
--- a/typo3/sysext/core/Tests/Unit/TypoScript/Parser/TypoScriptParserTest.php
+++ b/typo3/sysext/core/Tests/Unit/TypoScript/Parser/TypoScriptParserTest.php
@@ -385,6 +385,33 @@ class TypoScriptParserTest extends UnitTestCase
         self::assertEquals($expected, $this->typoScriptParser->errors[0][0]);
     }
 
+    public function invalidConditionsDataProvider(): array
+    {
+        return [
+            '[1 == 1]a' => ['[1 == 1]a', false],
+            '[1 == 1] # a comment' => ['[1 == 1] # a comment', false],
+            '[1 == 1]' => ['[1 == 1]', true],
+        ];
+    }
+
+    /**
+     * @test
+     * @dataProvider invalidConditionsDataProvider
+     * @param string $condition
+     * @param bool $isValid
+     */
+    public function invalidConditionsAreReported(string $condition, bool $isValid): void
+    {
+        $timeTrackerProphecy = $this->prophesize(TimeTracker::class);
+        GeneralUtility::setSingletonInstance(TimeTracker::class, $timeTrackerProphecy->reveal());
+
+        $this->typoScriptParser->parse($condition);
+        if (!$isValid) {
+            $expected = 'Line 0: Invalid condition found, any condition must end with "]": ' . $condition;
+            self::assertEquals($expected, $this->typoScriptParser->errors[0][0]);
+        }
+    }
+
     /**
      * @test
      */