Releases of happy-dom

779 stable releases, newest first. Release notes are kept for the last 90 days; older ones link to where they were published.

1. 21.0.3

   15 October 2026

   :construction_worker_man: Patch fixes

   • security

     Fixes security vulnerability where authorization header was forwarded when redirecting - By @capricorn86

2. 21.0.2

   15 October 2026

   :construction_worker_man: Patch fixes

   • security

     Fixes SSRF security vulnerability by doing a target-origin bypass in the proxy server in @happy-dom/server-renderer - By @capricorn86

3. 21.0.1

   12 October 2026

   :construction_worker_man: Patch fixes

   • Adds alias for enabling CSS and iframe loading to @happy-dom/server-renderer - By @capricorn86

4. 21.0.0

   11 October 2026

   :bomb: Breaking Changes

   • breaking

     Disables CSS and IFrame loading by default to prevent server-side request forgery (SSRF) - By @capricorn86

     • An attacker could embed <iframe> or <link rel="stylesheet"> elements in untrusted HTML to make Happy DOM send HTTP requests from the server to attacker-chosen URLs, including internal services. This could allow access to otherwise unreachable endpoints or trigger unintended actions, depending on the application and its network access.

     • The settings property disableCSSFileLoading has been deprecated

     • Added the new settings properties enableCSSFileLoading and enableIframePageLoading

   Show all 5 lines

5. 20.14.6

   8 October 2026

   :construction_worker_man: Patch fixes

   • security

     Fixes cookie scope forgery vulnerability - By @capricorn86

6. 20.14.5

   12 September 2026

   :construction_worker_man: Patch fixes

   • Preserve character references in comment data - By @hampustagerud in task #2409

7. 20.14.4

   12 September 2026

   :construction_worker_man: Patch fixes

   • End comments at the first comment end tag when it overlaps a comment start tag - By @hampustagerud in task #2407

8. 20.14.3

   9 September 2026

   :construction_worker_man: Patch fixes

   • Avoids cloning all properties in CSSPropertyManager.toString - By @erictheswift in task #2363

9. 20.14.2

   9 September 2026

   :construction_worker_man: Patch fixes

   • Fixes regression where not all CSS variables where resolved in getComputedStyle() - By @klaesra in task #2344

10. 20.14.1

    9 September 2026

    :construction_worker_man: Patch fixes

    • Invalidate the computed style cache for the whole subtree - By @matmannion and @capricorn86 in task #2366

11. 20.14.0

    3 September 2026

    :art: Features

    • Improves computed style cache - By @capricorn86 in task #2357

12. 20.13.2

    2 September 2026

    :construction_worker_man: Patch fixes

    • Fix problem with getComputedStyle with :host and :host-context selectors - By @capricorn86 in task #2349

13. 20.13.1

    2 September 2026

    :construction_worker_man: Patch fixes

    • GetComputedStyle should return inherited value when it is set to inherit - By @capricorn86 in task #2347

14. 20.13.0

    2 September 2026

    :art: Features

    • Adds support for :host psuedo query selector - By @capricorn86 in task #2345

15. 20.12.2

    2 September 2026

    :construction_worker_man: Patch fixes

    • Custom elements should be upgraded when connected to DOM - By @capricorn86 in task #2342

16. 20.12.1

    1 September 2026

    :art: Features

    • Adds support for kebab-case properties on CSSStyleDeclaration - By @capricorn86 in task #2256

    • Adds support for all Chromium CSS properties to CSSStyleDeclaration - By @capricorn86 in task #2256

      • Downloads a list from the Chromium project when compiling

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17. 20.12.0

    29 August 2026

    :art: Features

    • Adds support for Animation, AnimationTimeline, DocumentTimeline and KeyframeEffect - By @capricorn86

    • Adds support for Element.animate() - By @capricorn86

18. 20.11.15

    28 August 2026

    :construction_worker_man: Patch fixes

    • Fixes issue with upgrading custom element caused by previous release - By @capricorn86 in task #2331

19. 20.11.14

    28 August 2026

    :construction_worker_man: Patch fixes

    • Change prototype of element to the custom element when upgraded to keep the reference - By @capricorn86 in task #2331

      • The previous solution replaced the element with the custom element and copied it's properties, but this made any reference to the original element invalid

20. 20.11.13

    28 August 2026

    :construction_worker_man: Patch fixes

    • Copy event listeners when upgrading a custom element - By @capricorn86 in task #2329

21. 20.11.12

    27 August 2026

    :construction_worker_man: Patch fixes

    • Add check for if the node is still a parent during disconnect - By @capricorn86 in task #2322

22. 20.11.11

    27 August 2026

    :construction_worker_man: Patch fixes

    • Use proxy as parent node in Node.connectedToNode - By @diegohaz in task #2253

23. 20.11.10

    27 August 2026

    :construction_worker_man: Patch fixes

    • Return default validationMessage for built-in constraint violations - By @mixelburg in task #2187

24. 20.11.9

    27 August 2026

    :construction_worker_man: Patch fixes

    • Make sure that the element has been upgraded before invoking reaction callback in custom elements - By @capricorn86 in task #2317

25. 20.11.8

    26 August 2026

    :construction_worker_man: Patch fixes

    • Values pushed or assigned to the adoptedStyleSheet array should be validated - By @capricorn86 in task #2315

26. 20.11.7

    26 August 2026

    :construction_worker_man: Patch fixes

    • The properties Document.adoptedStyleSheets and ShadowRoot.adoptedStyleSheets should validate it's value - By @capricorn86 in task #2313

27. 20.11.6

    19 August 2026

    :construction_worker_man: Patch fixes

    • Updates docs for the global-registrator package - By @capricorn86 in task #2300

28. 20.11.5

    19 August 2026

    :construction_worker_man: Patch fixes

    • Allow explicit element types for querySelector (e.g. querySelector<HTMLInputElement>(".my-input")) - By @cyphercodes

29. 20.11.4

    19 August 2026

    :construction_worker_man: Patch fixes

    • Fixes the CORS check fetch() to match origins instead of host and protocol - By @rexxars in task #1490

30. 20.11.3

    19 August 2026

    :construction_worker_man: Patch fixes

    • Make document.links return a live HTMLCollection - By @bangseongbeom in task #2299

    • Copy labels array to prevent mutation of cached querySelectorAll result - By @mixelburg in task #2226

31. 20.11.2

    7 August 2026

    :construction_worker_man: Patch fixes

    • MutationObserver callback being GC'd due to orphaned WeakRef - By @mixelburg in task #2264

32. 20.11.1

    22 July 2026

    :construction_worker_man: Patch fixes

    • Improve performance of query selectors by avoiding construction of DOMException when not needed - By @@cyfung1031 in task #2228

33. 20.11.0

    18 July 2026

    :art: Features

    • Adds support for CookieStore API - By @TrevorBurnham in task #1864

    • Adds support for Element.checkVisibility() - By @capricorn86 in task #1506

34. 20.10.6

    17 June 2026

35. 20.10.5

    16 June 2026

36. 20.10.4

    15 June 2026

37. 20.10.3

    12 June 2026

38. 20.10.2

    6 June 2026

39. 20.10.1

    4 June 2026

40. 20.10.0

    3 June 2026

41. 20.9.0

    13 April 2026

42. 20.8.9

    26 March 2026

43. 20.8.8

    24 March 2026

44. 20.8.7

    23 March 2026

45. 20.8.6

    23 March 2026

46. 20.8.5

    23 March 2026

47. 20.8.4

    12 March 2026

48. 20.8.3

    3 March 2026

49. 20.8.2

    3 March 2026

50. 20.8.1

    2 March 2026