getsentry · chargome · Oct 2, 2025 · Oct 2, 2025 · Oct 2, 2025 · Oct 2, 2025
diff --git a/...browser-integration-tests/suites/tracing/request/fetch-baggage-property-values/subject.js b/...browser-integration-tests/suites/tracing/request/fetch-baggage-property-values/subject.js
@@ -0,0 +1,9 @@
+fetchButton.addEventListener('click', () => {
+  // W3C spec example: property values can contain = signs
+  // See: https://www.w3.org/TR/baggage/#example
+  fetch('http://sentry-test-site.example/fetch-test', {
+    headers: {
+      baggage: 'key1=value1;property1;property2,key2=value2,key3=value3; propertyKey=propertyValue',
+    },
+  });
+});
diff --git a/...wser-integration-tests/suites/tracing/request/fetch-baggage-property-values/template.html b/...wser-integration-tests/suites/tracing/request/fetch-baggage-property-values/template.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Fetch Baggage Property Values Test</title>
+  </head>
+  <body>
+    <button id="fetchButton">Make Fetch Request</button>
+  </body>
+</html>
diff --git a/...es/browser-integration-tests/suites/tracing/request/fetch-baggage-property-values/test.ts b/...es/browser-integration-tests/suites/tracing/request/fetch-baggage-property-values/test.ts
@@ -0,0 +1,41 @@
+import { expect } from '@playwright/test';
+import { TRACEPARENT_REGEXP } from '@sentry/core';
+import { sentryTest } from '../../../../utils/fixtures';
+import { shouldSkipTracingTest } from '../../../../utils/helpers';
+
+sentryTest(
+  'preserves baggage property values with equal signs in fetch requests',
+  async ({ getLocalTestUrl, page }) => {
+    if (shouldSkipTracingTest()) {
+      sentryTest.skip();
+    }
+
+    const url = await getLocalTestUrl({ testDir: __dirname });
+
+    const requestPromise = page.waitForRequest('http://sentry-test-site.example/fetch-test');
+
+    await page.goto(url);
+    await page.click('#fetchButton');
+
+    const request = await requestPromise;
+
+    const requestHeaders = request.headers();
+
+    expect(requestHeaders).toMatchObject({
+      'sentry-trace': expect.stringMatching(TRACEPARENT_REGEXP),
+    });
+
+    const baggageHeader = requestHeaders.baggage;
+    expect(baggageHeader).toBeDefined();
+
+    const baggageItems = baggageHeader.split(',').map(item => decodeURIComponent(item.trim()));
+
+    // Verify property values with = signs are preserved
+    expect(baggageItems).toContainEqual(expect.stringContaining('key1=value1;property1;property2'));
+    expect(baggageItems).toContainEqual(expect.stringContaining('key2=value2'));
+    expect(baggageItems).toContainEqual(expect.stringContaining('key3=value3; propertyKey=propertyValue'));
+
+    // Verify Sentry baggage is also present
+    expect(baggageHeader).toMatch(/sentry-/);
+  },
+);
diff --git a/...s/browser-integration-tests/suites/tracing/request/xhr-baggage-property-values/subject.js b/...s/browser-integration-tests/suites/tracing/request/xhr-baggage-property-values/subject.js
@@ -0,0 +1,8 @@
+const xhr = new XMLHttpRequest();
+
+xhr.open('GET', 'http://sentry-test-site.example/1');
+// W3C spec example: property values can contain = signs
+// See: https://www.w3.org/TR/baggage/#example
+xhr.setRequestHeader('baggage', 'key1=value1;property1;property2,key2=value2,key3=value3; propertyKey=propertyValue');
+
+xhr.send();
diff --git a/...ages/browser-integration-tests/suites/tracing/request/xhr-baggage-property-values/test.ts b/...ages/browser-integration-tests/suites/tracing/request/xhr-baggage-property-values/test.ts
@@ -0,0 +1,36 @@
+import { expect } from '@playwright/test';
+import { TRACEPARENT_REGEXP } from '@sentry/core';
+import { sentryTest } from '../../../../utils/fixtures';
+import { shouldSkipTracingTest } from '../../../../utils/helpers';
+
+sentryTest('preserves baggage property values with equal signs in XHR requests', async ({ getLocalTestUrl, page }) => {
+  if (shouldSkipTracingTest()) {
+    sentryTest.skip();
+  }
+
+  const url = await getLocalTestUrl({ testDir: __dirname });
+
+  const requestPromise = page.waitForRequest('http://sentry-test-site.example/1');
+
+  await page.goto(url);
+
+  const request = await requestPromise;
+
+  const requestHeaders = request.headers();
+
+  expect(requestHeaders).toMatchObject({
+    'sentry-trace': expect.stringMatching(TRACEPARENT_REGEXP),
+  });
+
+  const baggageHeader = requestHeaders.baggage;
+  expect(baggageHeader).toBeDefined();
+  const baggageItems = baggageHeader.split(',').map(item => decodeURIComponent(item.trim()));
+
+  // Verify property values with = signs are preserved
+  expect(baggageItems).toContainEqual(expect.stringContaining('key1=value1;property1;property2'));
+  expect(baggageItems).toContainEqual(expect.stringContaining('key2=value2'));
+  expect(baggageItems).toContainEqual(expect.stringContaining('key3=value3; propertyKey=propertyValue'));
+
+  // Verify Sentry baggage is also present
+  expect(baggageHeader).toMatch(/sentry-/);
+});
diff --git a/...ages/node-integration-tests/suites/express/sentry-trace/baggage-property-values/server.ts b/...ages/node-integration-tests/suites/express/sentry-trace/baggage-property-values/server.ts
@@ -0,0 +1,37 @@
+import * as Sentry from '@sentry/node';
+import { loggingTransport, startExpressServerAndSendPortToRunner } from '@sentry-internal/node-integration-tests';
+
+export type TestAPIResponse = { test_data: { host: string; 'sentry-trace': string; baggage: string } };
+
+Sentry.init({
+  dsn: 'https://[email protected]/1337',
+  release: '1.0',
+  environment: 'prod',
+  // disable requests to /express
+  tracePropagationTargets: [/^(?!.*express).*$/],
+  tracesSampleRate: 1.0,
+  transport: loggingTransport,
+});
+
+import cors from 'cors';
+import express from 'express';
+import http from 'http';
+
+const app = express();
+
+app.use(cors());
+
+app.get('/test/express-property-values', (req, res) => {
+  const incomingBaggage = req.headers.baggage;
+
+  // Forward the incoming baggage (which contains property values) to the outgoing request
+  // This tests that property values with = signs are preserved during parsing and re-serialization
+  const headers = http.get({ hostname: 'somewhere.not.sentry', headers: { baggage: incomingBaggage } }).getHeaders();
+
+  // Responding with the headers outgoing request headers back to the assertions.
+  res.send({ test_data: headers });
+});
+
+Sentry.setupExpressErrorHandler(app);
+
+startExpressServerAndSendPortToRunner(app);
diff --git a/...ckages/node-integration-tests/suites/express/sentry-trace/baggage-property-values/test.ts b/...ckages/node-integration-tests/suites/express/sentry-trace/baggage-property-values/test.ts
@@ -0,0 +1,28 @@
+import { afterAll, expect, test } from 'vitest';
+import { cleanupChildProcesses, createRunner } from '../../../../utils/runner';
+import type { TestAPIResponse } from './server';
+
+afterAll(() => {
+  cleanupChildProcesses();
+});
+
+test('should preserve baggage property values with equal signs (W3C spec compliance)', async () => {
+  const runner = createRunner(__dirname, 'server.ts').start();
+
+  // W3C spec example: https://www.w3.org/TR/baggage/#example
+  const response = await runner.makeRequest<TestAPIResponse>('get', '/test/express-property-values', {
+    headers: {
+      'sentry-trace': '12312012123120121231201212312012-1121201211212012-1',
+      baggage: 'key1=value1;property1;property2,key2=value2,key3=value3; propertyKey=propertyValue',
+    },
+  });
+
+  expect(response).toBeDefined();
+
+  // The baggage should be parsed and re-serialized, preserving property values with = signs
+  const baggageItems = response?.test_data.baggage?.split(',').map(item => decodeURIComponent(item.trim()));
+
+  expect(baggageItems).toContain('key1=value1;property1;property2');
+  expect(baggageItems).toContain('key2=value2');
+  expect(baggageItems).toContain('key3=value3; propertyKey=propertyValue');
+});
diff --git a/packages/core/src/utils/baggage.ts b/packages/core/src/utils/baggage.ts
@@ -113,17 +113,24 @@ export function parseBaggageHeader(
 function baggageHeaderToObject(baggageHeader: string): Record<string, string> {
   return baggageHeader
     .split(',')
-    .map(baggageEntry =>
-      baggageEntry.split('=').map(keyOrValue => {
+    .map(baggageEntry => {
+      const eqIdx = baggageEntry.indexOf('=');
+      if (eqIdx === -1) {
+        // Likely an invalid entry
+        return [];
+      }
+      const key = baggageEntry.slice(0, eqIdx);
+      const value = baggageEntry.slice(eqIdx + 1);
+      return [key, value].map(keyOrValue => {
         try {
           return decodeURIComponent(keyOrValue.trim());
         } catch {
           // We ignore errors here, e.g. if the value cannot be URL decoded.
           // This will then be skipped in the next step
           return;
         }
-      }),
-    )
+      });
+    })
     .reduce<Record<string, string>>((acc, [key, value]) => {
       if (key && value) {
         acc[key] = value;

diff --git a/packages/core/test/lib/utils/baggage.test.ts b/packages/core/test/lib/utils/baggage.test.ts
@@ -71,4 +71,16 @@ describe('parseBaggageHeader', () => {
     const actual = parseBaggageHeader(input);
     expect(actual).toStrictEqual(expectedOutput);
   });
+
+  test('should preserve property values with equal signs', () => {
+    // see https://www.w3.org/TR/baggage/#example
+    const baggageHeader = 'key1=value1;property1;property2, key2 = value2, key3=value3; propertyKey=propertyValue';
+    const result = parseBaggageHeader(baggageHeader);
+
+    expect(result).toStrictEqual({
+      key1: 'value1;property1;property2',
+      key2: 'value2',
+      key3: 'value3; propertyKey=propertyValue',
+    });
+  });
 });