With the latest update to Firefox 142, Mozilla is once again introducing various new features and improvements to its well-known browser. The coming improvements will help to better protect user privacy, and the developers have also addressed several security vulnerabilities.
Mozilla plans to release Firefox 143 on September 16th, 2025.
What’s new in Firefox 142?
Firefox 142 brings a curated news overview on the New Tab page instead of the Pocket service, which was discontinued in July. The news overview is organized by topic, and users can select or deselect certain topics. This feature is currently rolling out and may take a few days to land.
Mozilla is also rolling out a link preview feature, which can be selected via the right mouse button (i.e., context menu) and gives an impression of what you can expect if you were to click on that link. Optionally, a local “AI” can provide a summary of the destination page.
Another feature that will only impact a small number of Firefox users is extended profile management, which was introduced in Firefox 138. Profiles can now be marked with 28 icon options (up from 6), and you can also use your own icons. Similarly, since the introduction of vertical tabs in Firefox 136, browser add-ons can place their icon in the sidebar. If you don’t like this, you can now right-click on it.
Also, since the strictest tracking protection can lead to compatibility problems with certain websites, you can now enable an exceptions list. It’s up to you to decide which functions of a website are so important to you to warrant setting up an exception for them.
Mozilla’s commitment to user privacy
Mozilla differs from other major browser manufacturers in that it doesn’t spy on its users to sell advertising. Mozilla respects user privacy. To that end, all “AI” features are implemented locally and don’t involve passing data to cloud or web services. Even the check for revoked certificates is done without disclosing user activity—not even to Mozilla itself.
Mozilla has developed a mechanism for this with CRLite, which has been used since Firefox 137. From Firefox 142 onwards, the previous OCSP mechanism for domain certificates, which is also used by other browsers, will be switched off. CRLite is not only more data-efficient and therefore more discreet, but also faster and more efficient.
Security improvements in Firefox 142
Mozilla’s Security Advisory 2025-64 for Firefox 142 lists at least nine eliminated vulnerabilities. Mozilla categorizes two of the externally reported vulnerabilities as high risk. Malicious code can break out of the browser sandbox by exploiting an invalid pointer in an audio/video component for DRM-protected content (CVE-2025-9179) and a flaw in the Canvas2D graphics component can be exploited to bypass the same-origin policy (CVE-2025-9180).
Three entries in the Security Advisory concern an unspecified number of internally discovered vulnerabilities that are also considered high risk: CVE-2025-9184, CVE-2025-9185, CVE-2025-9187.
The other vulnerabilities that Mozilla’s developers have fixed in Firefox 142 are categorized as medium or low risk.
Further reading: Easy browser tweaks to boost your security
This article originally appeared on our sister publication PC-WELT and was translated and localized from German.
Author: Frank Ziemann, Contributor, PCWorld
Frank Ziemann has been working as a freelance author for sister site PC-WELT since 2005, writing news and test reports. His main topics are IT security (malware, antivirus, security gaps) and Internet technology.