Basilisk

Basilisk Development Team · Basilisk.Basilisk

A XUL-based web-browser built on top of the Unified XUL Platform (UXP). This browser is a close twin to pre-Servo Firefox in how it operates.

Basilisk is a free and Open Source XUL-based web browser, featuring the well-known Firefox-style interface and operation. It is based on the Goanna layout and rendering engine (a fork of Gecko) and builds on the Unified XUL Platform (UXP), which in turn is a fork of the Mozilla code base without Servo or Rust.

winget install --id Basilisk.Basilisk --exact --source winget

Latest 52.9.2026.03.09

Release Notes

UXP Changes:

  • Re-landed Xoroshiro128++ JavaScript PRNG to make it more robust while keeping high performance. This was previously backed out due to intermittent issues and crashes.
  • Implemented JavaScript SubmitEvent support for HTML forms.
  • Implemented JavaScript requestSubmit() for HTML forms.
  • Implemented JavaScript toSorted().
  • Implemented JavaScript toReversed().
  • Implemented top-level await support for JavaScript modules. See implementation notes.
  • Implemented pointer and hover CSS media queries.
  • Enabled hardware-accelerated decoding for VP9 videos (where possible).
  • Re-landed our expat library update, with fixes for large attribute parsing.
  • Updated the JPEG-XL library to 0.11.2 to pick up security and performance fixes, and applied a spot-fix for big-endian hardware.
  • Updated libtheora to 1.2.0.
  • Updated libvpx to 1.16.0 with various fixes to retain compatibility with older MacOS and PowerPC platforms.
  • Basilisk, from this version forward, allows unencrypted websocket connections to localhost addresses even when the calling document was served encrypted.
  • Fixed an issue in the new Cascade Layers implementation causing problems with UI elements and extensions.
  • Fixed several issues with the new ICU library implementation in UXP:
  • Fixed an issue where it was returning unexpected Unicode spaces in date strings instead of standard space characters, causing problems with web scripting.
  • Fixed an issue with plural forms for Shuar, Welsh and several Slavic languages.
  • Fixed an issue with letter dots in Lithuanian.
  • Fixed an issue with word-wrapping in Tibetan.
  • Fixed an intermittent browser crash related to removing cached image data, and improved image data cache handling as a whole.
  • Further improved compatibility with Mac on PowerPC hardware.
  • Restored support for building on 32-bit MacOS 10.6.
  • Applied miscellaneous fixes for building on MacOS 10.5 (Leopard) and 10.6 (Snow Leopard).
  • Fixed run-time issues on FreeBSD 15.*.
  • Fixed an issue with applying image filters on big-endian hardware.
  • Fixed an issue preventing bundled fonts from working properly on targets other than Windows or Linux-GTK.
  • Fixed crashes on long browsing sessions on sites making heavy use of WeakRef.
  • Built on UXP commit: a268e57967
  • Security issues addressed: CVE-2026-2806 (DiD), CVE-2026-2758, CVE-2026-2804, CVE-2026-2787 (DiD), CVE-2026-2757, CVE-2026-2773, CVE-2026-2779 (DiD), CVE-2026-2775, and several others that do not have a CVE designation.

Basilisk Changes:

  • LoongArch64 builds are now built on Loongnix Server 23.
  • Introduced Mac OS X 10.5 PowerPC builds.
  • We no longer differentiate between beta/alpha/etc. for builds. All builds are welcome here <3

Included Polyfills:

  • This release includes the following polyfills:
    • image.decode
    • Intl.DisplayNames
    • Intl.Segmenter
    • en-US only Intl.ListFormat
    • Microsoft-specific (Outlook, Azure, etc) webauthn shim
    • TextEncoderStream
    • ReadableStream pipeTo
    • ReadableStream pipeThrough
    • FinalizationRegistry

Basilisk Update Notes:

  • Added logging to the console when polyfills are loaded.
  • Improved spec compliance in ReadableStream polyfill.
  • Enabled getAnimations by default.

UXP Implementation Notes:

  • Top-level await for JavaScript modules has been implemented. This allows the use of the await keyword at the top level without a wrapper to force pseudo-synchronous processing in async modules. This completes the last landmark issue of our ES2022 compatibility. Most notably, the lack of this would result in websites using certain frameworks to render completely blank.

Installer type: nullsoft

Architecture Scope Download SHA256
x86 Download BABF9B376B75124D935BEA8F1001714DE1546832AD19BF560BD7500F89A2B10E
x64 Download BA8AD91128D28FD438F3DF51A201608CAE9A250B2CC6D9B7E637DD6B9830D3BE

Details

Homepage
https://www.basilisk-browser.org/download.html
License
MPL-2.0
Publisher
Basilisk Development Team
Support
https://www.basilisk-browser.org/contact.html
Privacy Policy
https://www.basilisk-browser.org/privacy.html
Copyright
Copyright ©2022-Present The Basilisk Development Team. All rights reserved.

Tags

browserinternetwebweb-browserwebpagexul

Older versions (6)

52.9.2026.01.23
Architecture Scope Download SHA256
x86 Download 2BD0EB23D1F3926CA33298FD1297ECEC948E0EC500FEBFCB0EFF93BB0AF35520
x64 Download D2E7454DEDC4C03649AF201BD37A8CC6622E516400B6A00EE208E5436654AB95
52.9.2025.10.10
Architecture Scope Download SHA256
x86 Download DA1493CD66A36BD57843BF2BCD2DBE8F0A1CD5F96AF2B5A1465C0A2B4989CB90
x64 Download E06729D01F22E710120CA9321B13884BA5823E5BB4F417BE1647847F068043EF
52.9.2025.07.04
Architecture Scope Download SHA256
x86 Download 95B9615C78DC626729353768ECBDD684DC9B1DFE9DB15FA36D296C8A1455ECA9
x64 Download 0BE9F04F23063FAC86239D1F436E4BC9822710FB7F9B397F76B9AFE5B51AF245
52.9.2025.06.13
Architecture Scope Download SHA256
x86 Download 0C9C868E546EF7D6553452492A75EEDA00AD9D8AED20197051963E0E80EFE15F
x64 Download A4D5F1DA0DDB4B038706B654FD126D32E8DD760F4BFB619C0006FE5B433DE6F5
52.9.2025.04.23
Architecture Scope Download SHA256
x86 Download B1C8B770D767FB21F3B320E6C98494D6219764468D3E7B2A419EFBD701E1D82D
x64 Download AEA84DC5CCA8D16388BE7E8D2A2B97D50C7C106AD3457D227F8657EA2FEC7A29
52.9.2025.02.22
Architecture Scope Download SHA256
x86 Download 757A542ED6969AD0E92BA4782A95B4EEF364A7A37B1AF92B8D1079FF5C130D6C
x64 Download 1A2066A4508D1C4AF417FE2DD3CBE55FE2F8D481BC3EB4617C7147416C3BCA27