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Mozilla released critical security updates for Firefox and Firefox ESR, and the Canadian Centre for Cyber Security urged organizations and users to apply them promptly. The affected versions are Firefox prior to 153, Firefox ESR prior to 140.13, and Firefox ESR prior to 115.38. The advisories were issued as patch guidance rather than a confirmed report of active exploitation, but they address vulnerabilities serious enough to warrant immediate attention.
Reporting on the release says Firefox 153 and the updated ESR branches include a broad set of fixes, with one source citing 216 vulnerabilities resolved. The update also addresses flaws tracked as CVE-2026-16411 and CVE-2026-16360, alongside multiple memory-safety issues described as potentially exploitable for arbitrary code execution. In addition to security remediation, the browser release includes privacy and isolation improvements such as stronger local network access protections and changes to cookie handling behavior.
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1 event from the most recent confirmed update back to the earliest known activity.
Mozilla published security advisories and released critical updates for Firefox 153, Firefox ESR 140.13, and Firefox ESR 115.38 to address vulnerabilities affecting prior versions. One source reports the release includes 216 security fixes, including CVE-2026-16411 and CVE-2026-16360, with several memory-safety issues noted as potentially exploitable for arbitrary code execution.
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Mozilla released security advisories addressing vulnerabilities in **Firefox** and **Firefox ESR**, prompting the Canadian Centre for Cyber Security to urge organizations and users to apply updates. The affected versions included Firefox releases prior to `149`, Firefox ESR releases prior to `115.34`, and Firefox ESR releases prior to `140.9`, according to the earlier advisory. A subsequent Mozilla advisory issued additional fixes for the same product lines, affecting Firefox versions prior to `149.0.2`, Firefox ESR versions prior to `115.34.1`, and Firefox ESR versions prior to `140.9.1`. The Canadian Centre for Cyber Security described the notices as vendor patch and mitigation guidance and advised administrators to review Mozilla’s bulletins and deploy the necessary updates across exposed systems.
Jun 29, 2026
Debian issued **DSA-6148-1** to ship a *firefox-esr* security update after Mozilla disclosed numerous vulnerabilities that could enable **arbitrary code execution**, **sandbox escape**, **same-origin policy bypass**, **information disclosure**, and **privilege escalation**. The advisory lists a large set of CVEs (including `CVE-2026-2757` through `CVE-2026-2793`, with gaps) and states fixes are available for Debian *oldstable* (bookworm) in **`firefox-esr` 140.8.0esr-1~deb12u1** (with the notice indicating corresponding updates for *stable* as well). The Canadian Centre for Cyber Security published **AV26-160**, relaying Mozilla’s February 24, 2026 advisories and urging organizations to apply updates for affected Mozilla products, including **Firefox ESR prior to 140.8**, **Firefox ESR prior to 115.33**, and **Firefox prior to 148**. The alert points administrators to Mozilla Foundation Security Advisories **2026-13**, **2026-14**, and **2026-15** as upstream references for the addressed vulnerabilities and remediation guidance.
Jun 29, 2026
Mozilla released security updates to address vulnerabilities in multiple Firefox products, including **Firefox 152**, **Firefox for iOS 152.0**, **Firefox ESR 140.12**, and **Firefox ESR 115.37**. The fixes were published through Mozilla Foundation Security Advisories **`MFSA 2026-56`** through **`MFSA 2026-59`**, with the Firefox for iOS update specifically covered in **`MFSA 2026-56`**. The Canadian Centre for Cyber Security issued alert **`AV26-604`** highlighting the advisories and warning that systems running versions prior to those releases remain affected. The agency urged users and administrators to review Mozilla’s guidance and apply the updates needed to remediate the disclosed flaws across supported desktop, mobile, and extended support browser versions.
Jun 30, 2026