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Mozilla has introduced native Containers in Firefox 153 as a preview feature, bringing core functionality from the long-running Multi-Account Containers extension directly into the browser. The built-in capability lets users separate browsing contexts such as work, shopping, personal use, and banking, isolating cookies and tracking data so they can stay signed in to multiple accounts in the same window while reducing cross-site tracking.
The preview allows tabs to be opened in specific containers and supports customization of container names, colors, and icons through Firefox settings. Mozilla said the feature was added in response to user demand for a browser-native implementation, but noted that the rollout is gradual and that some extension features are not yet included, such as certain per-site container rules; users who do not yet see the setting, or who need missing functionality, can continue using the existing add-on alongside the new implementation.
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Mozilla introduced an experimental local network access control capability in Firefox 153 that prompts users when websites attempt to reach devices or services on the local network. Mozilla said the feature is intended to stop malicious sites from probing vulnerable local devices or tracking users through local resources, and it is being rolled out gradually.
Mozilla released Firefox 153 as a stable version with browser-native Containers available as a preview feature. The rollout is gradual, and Mozilla said existing users can still rely on the Multi-Account Containers add-on while the built-in implementation matures.
Mozilla announced a preview of native Containers in Firefox 153, bringing Multi-Account Containers functionality directly into the browser. The preview lets users isolate cookies and tracking between browsing contexts and customize container settings, while some extension features remain unavailable.
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Mozilla has introduced significant enhancements to its anti-fingerprinting technology in Firefox 145, initially available in Private Browsing Mode and Enhanced Tracking Protection's Strict setting. The new measures, described as 'Phase 2' protections, further restrict websites' ability to collect unique device and browser characteristics, such as local fonts, hardware details, processor core counts, touch capabilities, and dock or taskbar dimensions. These updates build on previous efforts that had already reduced user trackability, with Mozilla now estimating that only about 20% of users can be uniquely fingerprinted under the new system. The protections also standardize certain outputs, like always reporting two CPU cores and reducing available screen height, to further limit the effectiveness of fingerprinting techniques. Mozilla cautions that completely eliminating all fingerprinting signals could disrupt legitimate website functionality, so users retain the option to disable these protections on specific pages if necessary. The company plans to make these privacy features the default for all users after further testing and optimization. These updates reflect Mozilla's ongoing commitment to user privacy and its proactive approach to countering increasingly sophisticated online tracking methods.
Jul 12, 2026
Mozilla patched multiple Firefox vulnerabilities, including a privacy flaw that let websites create hidden, stable identifiers without cookies by abusing the order of entries returned by `IndexedDB`. Researchers Dai Nguyen and Martin Bajanik of Fingerprint reported that the issue could persist across sessions and defeat protections expected from Firefox Private Browsing mode and Tor Browser’s **New Identity** feature, allowing sites to correlate activity that users believed was isolated. Mozilla addressed the issue under **Bug 2024220** in **Firefox 150** and **Firefox ESR 140.10.0**, with additional fixes included in **Firefox 150.0.3** and documented in Mozilla security advisories **MFSA-2026-32** and **MFSA-2026-45**. The Tor Project also incorporated the fix in **Tor Browser 15.0.10**, while Germany’s dCERT later published **Advisory 2026-1477** covering multiple Mozilla Firefox vulnerabilities.
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