diff --git a/extensions/notebook-renderers/src/stackTraceHelper.ts b/extensions/notebook-renderers/src/stackTraceHelper.ts
index d0d03c20441..230ff8e940c 100644
--- a/extensions/notebook-renderers/src/stackTraceHelper.ts
+++ b/extensions/notebook-renderers/src/stackTraceHelper.ts
@@ -32,8 +32,10 @@ export function formatStackTrace(stack: string, trustHtml: boolean): { formatted
 
 const formatSequence = /\u001b\[.+?m/g;
 const fileRegex = /File\s+(?:\u001b\[.+?m)?(.+):(\d+)/;
-const lineNumberRegex = /^((?:\u001b\[.+?m)?[ \->]+?)(\d+)(?:\u001b\[0m)?( .*)/;
-const cellRegex = /(?<prefix>Cell\s+(?:\u001b\[.+?m)?In\s*\[(?<executionCount>\d+)\],\s*)(?<lineLabel>line (?<lineNumber>\d+)).*/;
+// look for the "--->" before a line number
+const lineNumberRegex = /(-+>(?:\u001b\[[\d;]*m|\s)*)(\d+)(.*)/;
+// just capturing parts of "Cell In[3], line 2" with lots of formatting in between
+const cellRegex = /^(?<prefix>(?:\u001b\[[\d;]*m|\s)*Cell(?:\u001b\[[\d;]*m|\s)*In(?:\u001b\[[\d;]*m|\s)*\[(?<executionCount>\d+)\](?:\u001b\[[\d;]*m|\s|,)+)(?<lineLabel>line (?<lineNumber>\d+))[^\n]*$/m;
 // older versions of IPython ~8.3.0
 const inputRegex = /(?<prefix>Input\s+?(?:\u001b\[.+?m)(?<cellLabel>In\s*\[(?<executionCount>\d+)\]))(?<postfix>.*)/;
 
diff --git a/extensions/notebook-renderers/src/test/stackTraceHelper.test.ts b/extensions/notebook-renderers/src/test/stackTraceHelper.test.ts
index 41f7d10f9c8..6726296c469 100644
--- a/extensions/notebook-renderers/src/test/stackTraceHelper.test.ts
+++ b/extensions/notebook-renderers/src/test/stackTraceHelper.test.ts
@@ -45,7 +45,7 @@ suite('StackTraceHelper', () => {
 		assert.equal(errorLocation, '<a href=\'vscode-notebook-cell:?execution_count=3&line=2\'>line 2</a>');
 	});
 
-	test.skip('IPython stack line numbers are linkified for IPython 9.0.0', () => {
+	test('IPython stack line numbers are linkified for IPython 9.0.0', () => {
 		const stack =
 			'\u001b[31m---------------------------------------------------------------------------\u001b[39m\n' +
 			'\u001b[31mTypeError\u001b[39m                                 Traceback (most recent call last)\n' +
@@ -63,6 +63,20 @@ suite('StackTraceHelper', () => {
 		assert.equal(errorLocation, '<a href=\'vscode-notebook-cell:?execution_count=3&line=2\'>line 2</a>');
 	});
 
+	test('Does not have catastrophic backtracking https://github.com/microsoft/vscode/issues/251731', () => {
+		const stack =
+			'\u001b[31m---------------------------------------------------------------------------\u001b[39m\n' +
+			'\u001b[31mZeroDivisionError\u001b[39m                         Traceback (most recent call last)\n' +
+			'\u001b[36mCell\u001b[39m\u001b[36m \u001b[39m\u001b[32mIn[1]\u001b[39m\u001b[32m, line 2\u001b[39m\n\u001b[32m      1\u001b[39m raw_str = \u001b[33mr\u001b[39m\u001b[33m\"\u001b[39m\u001b[33m\\\u001b[39m\u001b[33ma\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mc\u001b[39m\u001b[33m\\\u001b[39m\u001b[33me\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mf\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mg\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mh\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mi\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mk\u001b[39m\u001b[33m\\\u001b[39m\u001b[33ml\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mm\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mn\u001b[39m\u001b[33m\\\u001b[39m\u001b[33mo\u001b[39m\u001b[33m\"\u001b[39m\n\u001b[32m----> \u001b[39m\u001b[32m2\u001b[39m \u001b[32;43m1\u001b[39;49m\u001b[43m/\u001b[49m\u001b[32;43m0\u001b[39;49m\n\n' +
+			'\u001b[31mZeroDivisionError\u001b[39m: division by zero\n';
+
+		const { formattedStack, errorLocation } = formatStackTrace(stack, true);
+		const cleanStack = stripAsciiFormatting(formattedStack);
+		assert.ok(cleanStack.indexOf('Cell In[1], <a href=\'vscode-notebook-cell:?execution_count=1&line=2\'>line 2</a>') > 0, 'Missing line link in ' + cleanStack);
+		assert.ok(cleanStack.indexOf('<a href=\'vscode-notebook-cell:?execution_count=1&line=2\'>2</a>') > 0, 'Missing frame link in ' + cleanStack);
+		assert.equal(errorLocation, '<a href=\'vscode-notebook-cell:?execution_count=1&line=2\'>line 2</a>');
+	});
+
 	test('Stack trace is not linkified when HTML is not trusted', () => {
 		const stack =
 			'\u001b[31m---------------------------------------------------------------------------\u001b[39m\n' +